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Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6 

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6:
  PM: PM QOS update fix
  Freezer / cgroup freezer: Update stale locking comments
  PM / platform_bus: Allow runtime PM by default
  i2c: Fix bus-level power management callbacks
  PM QOS update
  PM / Hibernate: Fix block_io.c printk warning
  PM / Hibernate: Group swap ops
  PM / Hibernate: Move the first_sector out of swsusp_write
  PM / Hibernate: Separate block_io
  PM / Hibernate: Snapshot cleanup
  FS / libfs: Implement simple_write_to_buffer
  PM / Hibernate: document open(/dev/snapshot) side effects
  PM / Runtime: Add sysfs debug files
  PM: Improve device power management document
  PM: Update device power management document
  PM: Allow runtime_suspend methods to call pm_schedule_suspend()
  PM: pm_wakeup - switch to using bool
This commit is contained in:
Linus Torvalds 2010-05-20 09:03:55 -07:00
parent fa5312d9e8 25f3a5a285
commit 46ee964509
31 changed files with 1251 additions and 949 deletions
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815
Documentation/power/devices.txt
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@ -1,7 +1,13 @@
Device Power Management
Copyright (c) 2010 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
Copyright (c) 2010 Alan Stern <stern@rowland.harvard.edu>
Most of the code in Linux is device drivers, so most of the Linux power
management code is also driver-specific. Most drivers will do very little;
others, especially for platforms with small batteries (like cell phones),
will do a lot.
management (PM) code is also driver-specific. Most drivers will do very
little; others, especially for platforms with small batteries (like cell
phones), will do a lot.
This writeup gives an overview of how drivers interact with system-wide
power management goals, emphasizing the models and interfaces that are
@ -15,9 +21,10 @@ Drivers will use one or both of these models to put devices into low-power
states:
System Sleep model:
Drivers can enter low power states as part of entering system-wide
low-power states like "suspend-to-ram", or (mostly for systems with
disks) "hibernate" (suspend-to-disk).
Drivers can enter low-power states as part of entering system-wide
low-power states like "suspend" (also known as "suspend-to-RAM"), or
(mostly for systems with disks) "hibernation" (also known as
"suspend-to-disk").
This is something that device, bus, and class drivers collaborate on
by implementing various role-specific suspend and resume methods to
@ -25,33 +32,41 @@ states:
them without loss of data.
Some drivers can manage hardware wakeup events, which make the system
leave that low-power state. This feature may be disabled using the
relevant /sys/devices/.../power/wakeup file; enabling it may cost some
power usage, but let the whole system enter low power states more often.
leave the low-power state. This feature may be enabled or disabled
using the relevant /sys/devices/.../power/wakeup file (for Ethernet
drivers the ioctl interface used by ethtool may also be used for this
purpose); enabling it may cost some power usage, but let the whole
system enter low-power states more often.
Runtime Power Management model:
Drivers may also enter low power states while the system is running,
independently of other power management activity. Upstream drivers
will normally not know (or care) if the device is in some low power
state when issuing requests; the driver will auto-resume anything
that's needed when it gets a request.
Devices may also be put into low-power states while the system is
running, independently of other power management activity in principle.
However, devices are not generally independent of each other (for
example, a parent device cannot be suspended unless all of its child
devices have been suspended). Moreover, depending on the bus type the
device is on, it may be necessary to carry out some bus-specific
operations on the device for this purpose. Devices put into low power
states at run time may require special handling during system-wide power
transitions (suspend or hibernation).
This doesn't have, or need much infrastructure; it's just something you
should do when writing your drivers. For example, clk_disable() unused
clocks as part of minimizing power drain for currently-unused hardware.
Of course, sometimes clusters of drivers will collaborate with each
other, which could involve task-specific power management.
For these reasons not only the device driver itself, but also the
appropriate subsystem (bus type, device type or device class) driver and
the PM core are involved in runtime power management. As in the system
sleep power management case, they need to collaborate by implementing
various role-specific suspend and resume methods, so that the hardware
is cleanly powered down and reactivated without data or service loss.
There's not a lot to be said about those low power states except that they
are very system-specific, and often device-specific. Also, that if enough
drivers put themselves into low power states (at "runtime"), the effect may be
the same as entering some system-wide low-power state (system sleep) ... and
that synergies exist, so that several drivers using runtime pm might put the
system into a state where even deeper power saving options are available.
There's not a lot to be said about those low-power states except that they are
very system-specific, and often device-specific. Also, that if enough devices
have been put into low-power states (at runtime), the effect may be very similar
to entering some system-wide low-power state (system sleep) ... and that
synergies exist, so that several drivers using runtime PM might put the system
into a state where even deeper power saving options are available.
Most suspended devices will have quiesced all I/O: no more DMA or irqs, no
more data read or written, and requests from upstream drivers are no longer
accepted. A given bus or platform may have different requirements though.
Most suspended devices will have quiesced all I/O: no more DMA or IRQs (except
for wakeup events), no more data read or written, and requests from upstream
drivers are no longer accepted. A given bus or platform may have different
requirements though.
Examples of hardware wakeup events include an alarm from a real time clock,
network wake-on-LAN packets, keyboard or mouse activity, and media insertion
@ -60,129 +75,152 @@ or removal (for PCMCIA, MMC/SD, USB, and so on).
Interfaces for Entering System Sleep States
===========================================
Most of the programming interfaces a device driver needs to know about
relate to that first model: entering a system-wide low power state,
rather than just minimizing power consumption by one device.
There are programming interfaces provided for subsystems (bus type, device type,
device class) and device drivers to allow them to participate in the power
management of devices they are concerned with. These interfaces cover both
system sleep and runtime power management.
Bus Driver Methods
------------------
The core methods to suspend and resume devices reside in struct bus_type.
These are mostly of interest to people writing infrastructure for busses
like PCI or USB, or because they define the primitives that device drivers
may need to apply in domain-specific ways to their devices:
Device Power Management Operations
----------------------------------
Device power management operations, at the subsystem level as well as at the
device driver level, are implemented by defining and populating objects of type
struct dev_pm_ops:
struct bus_type {
...
int (*suspend)(struct device *dev, pm_message_t state);
int (*resume)(struct device *dev);
struct dev_pm_ops {
int (*prepare)(struct device *dev);
void (*complete)(struct device *dev);
int (*suspend)(struct device *dev);
int (*resume)(struct device *dev);
int (*freeze)(struct device *dev);
int (*thaw)(struct device *dev);
int (*poweroff)(struct device *dev);
int (*restore)(struct device *dev);
int (*suspend_noirq)(struct device *dev);
int (*resume_noirq)(struct device *dev);
int (*freeze_noirq)(struct device *dev);
int (*thaw_noirq)(struct device *dev);
int (*poweroff_noirq)(struct device *dev);
int (*restore_noirq)(struct device *dev);
int (*runtime_suspend)(struct device *dev);
int (*runtime_resume)(struct device *dev);
int (*runtime_idle)(struct device *dev);
};
Bus drivers implement those methods as appropriate for the hardware and
the drivers using it; PCI works differently from USB, and so on. Not many
people write bus drivers; most driver code is a "device driver" that
builds on top of bus-specific framework code.
This structure is defined in include/linux/pm.h and the methods included in it
are also described in that file. Their roles will be explained in what follows.
For now, it should be sufficient to remember that the last three methods are
specific to runtime power management while the remaining ones are used during
system-wide power transitions.
There also is a deprecated "old" or "legacy" interface for power management
operations available at least for some subsystems. This approach does not use
struct dev_pm_ops objects and it is suitable only for implementing system sleep
power management methods. Therefore it is not described in this document, so
please refer directly to the source code for more information about it.
Subsystem-Level Methods
-----------------------
The core methods to suspend and resume devices reside in struct dev_pm_ops
pointed to by the pm member of struct bus_type, struct device_type and
struct class. They are mostly of interest to the people writing infrastructure
for buses, like PCI or USB, or device type and device class drivers.
Bus drivers implement these methods as appropriate for the hardware and the
drivers using it; PCI works differently from USB, and so on. Not many people
write subsystem-level drivers; most driver code is a "device driver" that builds
on top of bus-specific framework code.
For more information on these driver calls, see the description later;
they are called in phases for every device, respecting the parent-child
sequencing in the driver model tree. Note that as this is being written,
only the suspend() and resume() are widely available; not many bus drivers
leverage all of those phases, or pass them down to lower driver levels.
sequencing in the driver model tree.
/sys/devices/.../power/wakeup files
-----------------------------------
All devices in the driver model have two flags to control handling of
wakeup events, which are hardware signals that can force the device and/or
system out of a low power state. These are initialized by bus or device
driver code using device_init_wakeup(dev,can_wakeup).
All devices in the driver model have two flags to control handling of wakeup
events (hardware signals that can force the device and/or system out of a low
power state). These flags are initialized by bus or device driver code using
device_set_wakeup_capable() and device_set_wakeup_enable(), defined in
include/linux/pm_wakeup.h.
The "can_wakeup" flag just records whether the device (and its driver) can
physically support wakeup events. When that flag is clear, the sysfs
"wakeup" file is empty, and device_may_wakeup() returns false.
physically support wakeup events. The device_set_wakeup_capable() routine
affects this flag. The "should_wakeup" flag controls whether the device should
try to use its wakeup mechanism. device_set_wakeup_enable() affects this flag;
for the most part drivers should not change its value. The initial value of
should_wakeup is supposed to be false for the majority of devices; the major
exceptions are power buttons, keyboards, and Ethernet adapters whose WoL
(wake-on-LAN) feature has been set up with ethtool.
For devices that can issue wakeup events, a separate flag controls whether
that device should try to use its wakeup mechanism. The initial value of
device_may_wakeup() will be true, so that the device's "wakeup" file holds
the value "enabled". Userspace can change that to "disabled" so that
device_may_wakeup() returns false; or change it back to "enabled" (so that
it returns true again).
Whether or not a device is capable of issuing wakeup events is a hardware
matter, and the kernel is responsible for keeping track of it. By contrast,
whether or not a wakeup-capable device should issue wakeup events is a policy
decision, and it is managed by user space through a sysfs attribute: the
power/wakeup file. User space can write the strings "enabled" or "disabled" to
set or clear the should_wakeup flag, respectively. Reads from the file will
return the corresponding string if can_wakeup is true, but if can_wakeup is
false then reads will return an empty string, to indicate that the device
doesn't support wakeup events. (But even though the file appears empty, writes
will still affect the should_wakeup flag.)
The device_may_wakeup() routine returns true only if both flags are set.
Drivers should check this routine when putting devices in a low-power state
during a system sleep transition, to see whether or not to enable the devices'
wakeup mechanisms. However for runtime power management, wakeup events should
be enabled whenever the device and driver both support them, regardless of the
should_wakeup flag.
EXAMPLE: PCI Device Driver Methods
-----------------------------------
PCI framework software calls these methods when the PCI device driver bound
to a device device has provided them:
/sys/devices/.../power/control files
------------------------------------
Each device in the driver model has a flag to control whether it is subject to
runtime power management. This flag, called runtime_auto, is initialized by the
bus type (or generally subsystem) code using pm_runtime_allow() or
pm_runtime_forbid(); the default is to allow runtime power management.
struct pci_driver {
...
int (*suspend)(struct pci_device *pdev, pm_message_t state);
int (*suspend_late)(struct pci_device *pdev, pm_message_t state);
The setting can be adjusted by user space by writing either "on" or "auto" to
the device's power/control sysfs file. Writing "auto" calls pm_runtime_allow(),
setting the flag and allowing the device to be runtime power-managed by its
driver. Writing "on" calls pm_runtime_forbid(), clearing the flag, returning
the device to full power if it was in a low-power state, and preventing the
device from being runtime power-managed. User space can check the current value
of the runtime_auto flag by reading the file.
int (*resume_early)(struct pci_device *pdev);
int (*resume)(struct pci_device *pdev);
};
The device's runtime_auto flag has no effect on the handling of system-wide
power transitions. In particular, the device can (and in the majority of cases
should and will) be put into a low-power state during a system-wide transition
to a sleep state even though its runtime_auto flag is clear.
Drivers will implement those methods, and call PCI-specific procedures
like pci_set_power_state(), pci_enable_wake(), pci_save_state(), and
pci_restore_state() to manage PCI-specific mechanisms. (PCI config space
could be saved during driver probe, if it weren't for the fact that some
systems rely on userspace tweaking using setpci.) Devices are suspended
before their bridges enter low power states, and likewise bridges resume
before their devices.
For more information about the runtime power management framework, refer to
Documentation/power/runtime_pm.txt.
Upper Layers of Driver Stacks
-----------------------------
Device drivers generally have at least two interfaces, and the methods
sketched above are the ones which apply to the lower level (nearer PCI, USB,
or other bus hardware). The network and block layers are examples of upper
level interfaces, as is a character device talking to userspace.
Power management requests normally need to flow through those upper levels,
which often use domain-oriented requests like "blank that screen". In
some cases those upper levels will have power management intelligence that
relates to end-user activity, or other devices that work in cooperation.
When those interfaces are structured using class interfaces, there is a
standard way to have the upper layer stop issuing requests to a given
class device (and restart later):
struct class {
...
int (*suspend)(struct device *dev, pm_message_t state);
int (*resume)(struct device *dev);
};
Those calls are issued in specific phases of the process by which the
system enters a low power "suspend" state, or resumes from it.
Calling Drivers to Enter System Sleep States
============================================
When the system enters a low power state, each device's driver is asked
to suspend the device by putting it into state compatible with the target
Calling Drivers to Enter and Leave System Sleep States
======================================================
When the system goes into a sleep state, each device's driver is asked to
suspend the device by putting it into a state compatible with the target
system state. That's usually some version of "off", but the details are
system-specific. Also, wakeup-enabled devices will usually stay partly
functional in order to wake the system.
When the system leaves that low power state, the device's driver is asked
to resume it. The suspend and resume operations always go together, and
both are multi-phase operations.
When the system leaves that low-power state, the device's driver is asked to
resume it by returning it to full power. The suspend and resume operations
always go together, and both are multi-phase operations.
For simple drivers, suspend might quiesce the device using the class code
and then turn its hardware as "off" as possible with late_suspend. The
For simple drivers, suspend might quiesce the device using class code
and then turn its hardware as "off" as possible during suspend_noirq. The
matching resume calls would then completely reinitialize the hardware
before reactivating its class I/O queues.
More power-aware drivers drivers will use more than one device low power
state, either at runtime or during system sleep states, and might trigger
system wakeup events.
More power-aware drivers might prepare the devices for triggering system wakeup
events.
Call Sequence Guarantees
------------------------
To ensure that bridges and similar links needed to talk to a device are
To ensure that bridges and similar links needing to talk to a device are
available when the device is suspended or resumed, the device tree is
walked in a bottom-up order to suspend devices. A top-down order is
used to resume those devices.
@ -194,67 +232,310 @@ its parent; and can't be removed or suspended after that parent.
The policy is that the device tree should match hardware bus topology.
(Or at least the control bus, for devices which use multiple busses.)
In particular, this means that a device registration may fail if the parent of
the device is suspending (ie. has been chosen by the PM core as the next
the device is suspending (i.e. has been chosen by the PM core as the next
device to suspend) or has already suspended, as well as after all of the other
devices have been suspended. Device drivers must be prepared to cope with such
situations.
Suspending Devices
------------------
Suspending a given device is done in several phases. Suspending the
system always includes every phase, executing calls for every device
before the next phase begins. Not all busses or classes support all
these callbacks; and not all drivers use all the callbacks.
System Power Management Phases
------------------------------
Suspending or resuming the system is done in several phases. Different phases
are used for standby or memory sleep states ("suspend-to-RAM") and the
hibernation state ("suspend-to-disk"). Each phase involves executing callbacks
for every device before the next phase begins. Not all busses or classes
support all these callbacks and not all drivers use all the callbacks. The
various phases always run after tasks have been frozen and before they are
unfrozen. Furthermore, the *_noirq phases run at a time when IRQ handlers have
been disabled (except for those marked with the IRQ_WAKEUP flag).
The phases are seen by driver notifications issued in this order:
Most phases use bus, type, and class callbacks (that is, methods defined in
dev->bus->pm, dev->type->pm, and dev->class->pm). The prepare and complete
phases are exceptions; they use only bus callbacks. When multiple callbacks
are used in a phase, they are invoked in the order: <class, type, bus> during
power-down transitions and in the opposite order during power-up transitions.
For example, during the suspend phase the PM core invokes
1 class.suspend(dev, message) is called after tasks are frozen, for
devices associated with a class that has such a method. This
method may sleep.
dev->class->pm.suspend(dev);
dev->type->pm.suspend(dev);
dev->bus->pm.suspend(dev);
Since I/O activity usually comes from such higher layers, this is
a good place to quiesce all drivers of a given type (and keep such
code out of those drivers).
before moving on to the next device, whereas during the resume phase the core
invokes
2 bus.suspend(dev, message) is called next. This method may sleep,
and is often morphed into a device driver call with bus-specific
parameters and/or rules.
dev->bus->pm.resume(dev);
dev->type->pm.resume(dev);
dev->class->pm.resume(dev);
This call should handle parts of device suspend logic that require
sleeping. It probably does work to quiesce the device which hasn't
been abstracted into class.suspend().
These callbacks may in turn invoke device- or driver-specific methods stored in
dev->driver->pm, but they don't have to.
The pm_message_t parameter is currently used to refine those semantics
(described later).
At the end of those phases, drivers should normally have stopped all I/O
transactions (DMA, IRQs), saved enough state that they can re-initialize
or restore previous state (as needed by the hardware), and placed the
device into a low-power state. On many platforms they will also use
clk_disable() to gate off one or more clock sources; sometimes they will
also switch off power supplies, or reduce voltages. Drivers which have
runtime PM support may already have performed some or all of the steps
needed to prepare for the upcoming system sleep state.
Entering System Suspend
-----------------------
When the system goes into the standby or memory sleep state, the phases are:
When any driver sees that its device_can_wakeup(dev), it should make sure
to use the relevant hardware signals to trigger a system wakeup event.
For example, enable_irq_wake() might identify GPIO signals hooked up to
a switch or other external hardware, and pci_enable_wake() does something
similar for PCI's PME# signal.
prepare, suspend, suspend_noirq.
If a driver (or bus, or class) fails it suspend method, the system won't
enter the desired low power state; it will resume all the devices it's
suspended so far.
1. The prepare phase is meant to prevent races by preventing new devices
from being registered; the PM core would never know that all the
children of a device had been suspended if new children could be
registered at will. (By contrast, devices may be unregistered at any
time.) Unlike the other suspend-related phases, during the prepare
phase the device tree is traversed top-down.
Note that drivers may need to perform different actions based on the target
system lowpower/sleep state. At this writing, there are only platform
specific APIs through which drivers could determine those target states.
The prepare phase uses only a bus callback. After the callback method
returns, no new children may be registered below the device. The method
may also prepare the device or driver in some way for the upcoming
system power transition, but it should not put the device into a
low-power state.
2. The suspend methods should quiesce the device to stop it from performing
I/O. They also may save the device registers and put it into the
appropriate low-power state, depending on the bus type the device is on,
and they may enable wakeup events.
3. The suspend_noirq phase occurs after IRQ handlers have been disabled,
which means that the driver's interrupt handler will not be called while
the callback method is running. The methods should save the values of
the device's registers that weren't saved previously and finally put the
device into the appropriate low-power state.
The majority of subsystems and device drivers need not implement this
callback. However, bus types allowing devices to share interrupt
vectors, like PCI, generally need it; otherwise a driver might encounter
an error during the suspend phase by fielding a shared interrupt
generated by some other device after its own device had been set to low
power.
At the end of these phases, drivers should have stopped all I/O transactions
(DMA, IRQs), saved enough state that they can re-initialize or restore previous
state (as needed by the hardware), and placed the device into a low-power state.
On many platforms they will gate off one or more clock sources; sometimes they
will also switch off power supplies or reduce voltages. (Drivers supporting
runtime PM may already have performed some or all of these steps.)
If device_may_wakeup(dev) returns true, the device should be prepared for
generating hardware wakeup signals to trigger a system wakeup event when the
system is in the sleep state. For example, enable_irq_wake() might identify
GPIO signals hooked up to a switch or other external hardware, and
pci_enable_wake() does something similar for the PCI PME signal.
If any of these callbacks returns an error, the system won't enter the desired
low-power state. Instead the PM core will unwind its actions by resuming all
the devices that were suspended.
Leaving System Suspend
----------------------
When resuming from standby or memory sleep, the phases are:
resume_noirq, resume, complete.
1. The resume_noirq callback methods should perform any actions needed
before the driver's interrupt handlers are invoked. This generally
means undoing the actions of the suspend_noirq phase. If the bus type
permits devices to share interrupt vectors, like PCI, the method should
bring the device and its driver into a state in which the driver can
recognize if the device is the source of incoming interrupts, if any,
and handle them correctly.
For example, the PCI bus type's ->pm.resume_noirq() puts the device into
the full-power state (D0 in the PCI terminology) and restores the
standard configuration registers of the device. Then it calls the
device driver's ->pm.resume_noirq() method to perform device-specific
actions.
2. The resume methods should bring the the device back to its operating
state, so that it can perform normal I/O. This generally involves
undoing the actions of the suspend phase.
3. The complete phase uses only a bus callback. The method should undo the
actions of the prepare phase. Note, however, that new children may be
registered below the device as soon as the resume callbacks occur; it's
not necessary to wait until the complete phase.
At the end of these phases, drivers should be as functional as they were before
suspending: I/O can be performed using DMA and IRQs, and the relevant clocks are
gated on. Even if the device was in a low-power state before the system sleep
because of runtime power management, afterwards it should be back in its
full-power state. There are multiple reasons why it's best to do this; they are
discussed in more detail in Documentation/power/runtime_pm.txt.
However, the details here may again be platform-specific. For example,
some systems support multiple "run" states, and the mode in effect at
the end of resume might not be the one which preceded suspension.
That means availability of certain clocks or power supplies changed,
which could easily affect how a driver works.
Drivers need to be able to handle hardware which has been reset since the
suspend methods were called, for example by complete reinitialization.
This may be the hardest part, and the one most protected by NDA'd documents
and chip errata. It's simplest if the hardware state hasn't changed since
the suspend was carried out, but that can't be guaranteed (in fact, it ususally
is not the case).
Drivers must also be prepared to notice that the device has been removed
while the system was powered down, whenever that's physically possible.
PCMCIA, MMC, USB, Firewire, SCSI, and even IDE are common examples of busses
where common Linux platforms will see such removal. Details of how drivers
will notice and handle such removals are currently bus-specific, and often
involve a separate thread.
These callbacks may return an error value, but the PM core will ignore such
errors since there's nothing it can do about them other than printing them in
the system log.
Entering Hibernation
--------------------
Hibernating the system is more complicated than putting it into the standby or
memory sleep state, because it involves creating and saving a system image.
Therefore there are more phases for hibernation, with a different set of
callbacks. These phases always run after tasks have been frozen and memory has
been freed.
The general procedure for hibernation is to quiesce all devices (freeze), create
an image of the system memory while everything is stable, reactivate all
devices (thaw), write the image to permanent storage, and finally shut down the
system (poweroff). The phases used to accomplish this are:
prepare, freeze, freeze_noirq, thaw_noirq, thaw, complete,
prepare, poweroff, poweroff_noirq
1. The prepare phase is discussed in the "Entering System Suspend" section
above.
2. The freeze methods should quiesce the device so that it doesn't generate
IRQs or DMA, and they may need to save the values of device registers.
However the device does not have to be put in a low-power state, and to
save time it's best not to do so. Also, the device should not be
prepared to generate wakeup events.
3. The freeze_noirq phase is analogous to the suspend_noirq phase discussed
above, except again that the device should not be put in a low-power
state and should not be allowed to generate wakeup events.
At this point the system image is created. All devices should be inactive and
the contents of memory should remain undisturbed while this happens, so that the
image forms an atomic snapshot of the system state.
4. The thaw_noirq phase is analogous to the resume_noirq phase discussed
above. The main difference is that its methods can assume the device is
in the same state as at the end of the freeze_noirq phase.
5. The thaw phase is analogous to the resume phase discussed above. Its
methods should bring the device back to an operating state, so that it
can be used for saving the image if necessary.
6. The complete phase is discussed in the "Leaving System Suspend" section
above.
At this point the system image is saved, and the devices then need to be
prepared for the upcoming system shutdown. This is much like suspending them
before putting the system into the standby or memory sleep state, and the phases
are similar.
7. The prepare phase is discussed above.
8. The poweroff phase is analogous to the suspend phase.
9. The poweroff_noirq phase is analogous to the suspend_noirq phase.
The poweroff and poweroff_noirq callbacks should do essentially the same things
as the suspend and suspend_noirq callbacks. The only notable difference is that
they need not store the device register values, because the registers should
already have been stored during the freeze or freeze_noirq phases.
Leaving Hibernation
-------------------
Resuming from hibernation is, again, more complicated than resuming from a sleep
state in which the contents of main memory are preserved, because it requires
a system image to be loaded into memory and the pre-hibernation memory contents
to be restored before control can be passed back to the image kernel.
Although in principle, the image might be loaded into memory and the
pre-hibernation memory contents restored by the boot loader, in practice this
can't be done because boot loaders aren't smart enough and there is no
established protocol for passing the necessary information. So instead, the
boot loader loads a fresh instance of the kernel, called the boot kernel, into
memory and passes control to it in the usual way. Then the boot kernel reads
the system image, restores the pre-hibernation memory contents, and passes
control to the image kernel. Thus two different kernels are involved in
resuming from hibernation. In fact, the boot kernel may be completely different
from the image kernel: a different configuration and even a different version.
This has important consequences for device drivers and their subsystems.
To be able to load the system image into memory, the boot kernel needs to
include at least a subset of device drivers allowing it to access the storage
medium containing the image, although it doesn't need to include all of the
drivers present in the image kernel. After the image has been loaded, the
devices managed by the boot kernel need to be prepared for passing control back
to the image kernel. This is very similar to the initial steps involved in
creating a system image, and it is accomplished in the same way, using prepare,
freeze, and freeze_noirq phases. However the devices affected by these phases
are only those having drivers in the boot kernel; other devices will still be in
whatever state the boot loader left them.
Should the restoration of the pre-hibernation memory contents fail, the boot
kernel would go through the "thawing" procedure described above, using the
thaw_noirq, thaw, and complete phases, and then continue running normally. This
happens only rarely. Most often the pre-hibernation memory contents are
restored successfully and control is passed to the image kernel, which then
becomes responsible for bringing the system back to the working state.
To achieve this, the image kernel must restore the devices' pre-hibernation
functionality. The operation is much like waking up from the memory sleep
state, although it involves different phases:
restore_noirq, restore, complete
1. The restore_noirq phase is analogous to the resume_noirq phase.
2. The restore phase is analogous to the resume phase.
3. The complete phase is discussed above.
The main difference from resume[_noirq] is that restore[_noirq] must assume the
device has been accessed and reconfigured by the boot loader or the boot kernel.
Consequently the state of the device may be different from the state remembered
from the freeze and freeze_noirq phases. The device may even need to be reset
and completely re-initialized. In many cases this difference doesn't matter, so
the resume[_noirq] and restore[_norq] method pointers can be set to the same
routines. Nevertheless, different callback pointers are used in case there is a
situation where it actually matters.
System Devices
--------------
System devices (sysdevs) follow a slightly different API, which can be found in
include/linux/sysdev.h
drivers/base/sys.c
System devices will be suspended with interrupts disabled, and after all other
devices have been suspended. On resume, they will be resumed before any other
devices, and also with interrupts disabled. These things occur in special
"sysdev_driver" phases, which affect only system devices.
Thus, after the suspend_noirq (or freeze_noirq or poweroff_noirq) phase, when
the non-boot CPUs are all offline and IRQs are disabled on the remaining online
CPU, then a sysdev_driver.suspend phase is carried out, and the system enters a
sleep state (or a system image is created). During resume (or after the image
has been created or loaded) a sysdev_driver.resume phase is carried out, IRQs
are enabled on the only online CPU, the non-boot CPUs are enabled, and the
resume_noirq (or thaw_noirq or restore_noirq) phase begins.
Code to actually enter and exit the system-wide low power state sometimes
involves hardware details that are only known to the boot firmware, and
may leave a CPU running software (from SRAM or flash memory) that monitors
the system and manages its wakeup sequence.
Device Low Power (suspend) States
---------------------------------
Device low-power states aren't very standard. One device might only handle
Device low-power states aren't standard. One device might only handle
"on" and "off, while another might support a dozen different versions of
"on" (how many engines are active?), plus a state that gets back to "on"
faster than from a full "off".
@ -265,7 +546,7 @@ PCI device may not perform DMA or issue IRQs, and any wakeup events it
issues would be issued through the PME# bus signal. Plus, there are
several PCI-standard device states, some of which are optional.
In contrast, integrated system-on-chip processors often use irqs as the
In contrast, integrated system-on-chip processors often use IRQs as the
wakeup event sources (so drivers would call enable_irq_wake) and might
be able to treat DMA completion as a wakeup event (sometimes DMA can stay
active too, it'd only be the CPU and some peripherals that sleep).
@ -284,120 +565,17 @@ ways; the aforementioned LCD might be active in one product's "standby",
but a different product using the same SOC might work differently.
Meaning of pm_message_t.event
-----------------------------
Parameters to suspend calls include the device affected and a message of
type pm_message_t, which has one field: the event. If driver does not
recognize the event code, suspend calls may abort the request and return
a negative errno. However, most drivers will be fine if they implement
PM_EVENT_SUSPEND semantics for all messages.
Power Management Notifiers
--------------------------
There are some operations that cannot be carried out by the power management
callbacks discussed above, because the callbacks occur too late or too early.
To handle these cases, subsystems and device drivers may register power
management notifiers that are called before tasks are frozen and after they have
been thawed. Generally speaking, the PM notifiers are suitable for performing
actions that either require user space to be available, or at least won't
interfere with user space.
The event codes are used to refine the goal of suspending the device, and
mostly matter when creating or resuming system memory image snapshots, as
used with suspend-to-disk:
PM_EVENT_SUSPEND -- quiesce the driver and put hardware into a low-power
state. When used with system sleep states like "suspend-to-RAM" or
"standby", the upcoming resume() call will often be able to rely on
state kept in hardware, or issue system wakeup events.
PM_EVENT_HIBERNATE -- Put hardware into a low-power state and enable wakeup
events as appropriate. It is only used with hibernation
(suspend-to-disk) and few devices are able to wake up the system from
this state; most are completely powered off.
PM_EVENT_FREEZE -- quiesce the driver, but don't necessarily change into
any low power mode. A system snapshot is about to be taken, often
followed by a call to the driver's resume() method. Neither wakeup
events nor DMA are allowed.
PM_EVENT_PRETHAW -- quiesce the driver, knowing that the upcoming resume()
will restore a suspend-to-disk snapshot from a different kernel image.
Drivers that are smart enough to look at their hardware state during
resume() processing need that state to be correct ... a PRETHAW could
be used to invalidate that state (by resetting the device), like a
shutdown() invocation would before a kexec() or system halt. Other
drivers might handle this the same way as PM_EVENT_FREEZE. Neither
wakeup events nor DMA are allowed.
To enter "standby" (ACPI S1) or "Suspend to RAM" (STR, ACPI S3) states, or
the similarly named APM states, only PM_EVENT_SUSPEND is used; the other event
codes are used for hibernation ("Suspend to Disk", STD, ACPI S4).
There's also PM_EVENT_ON, a value which never appears as a suspend event
but is sometimes used to record the "not suspended" device state.
Resuming Devices
----------------
Resuming is done in multiple phases, much like suspending, with all
devices processing each phase's calls before the next phase begins.
The phases are seen by driver notifications issued in this order:
1 bus.resume(dev) reverses the effects of bus.suspend(). This may
be morphed into a device driver call with bus-specific parameters;
implementations may sleep.
2 class.resume(dev) is called for devices associated with a class
that has such a method. Implementations may sleep.
This reverses the effects of class.suspend(), and would usually
reactivate the device's I/O queue.
At the end of those phases, drivers should normally be as functional as
they were before suspending: I/O can be performed using DMA and IRQs, and
the relevant clocks are gated on. The device need not be "fully on"; it
might be in a runtime lowpower/suspend state that acts as if it were.
However, the details here may again be platform-specific. For example,
some systems support multiple "run" states, and the mode in effect at
the end of resume() might not be the one which preceded suspension.
That means availability of certain clocks or power supplies changed,
which could easily affect how a driver works.
Drivers need to be able to handle hardware which has been reset since the
suspend methods were called, for example by complete reinitialization.
This may be the hardest part, and the one most protected by NDA'd documents
and chip errata. It's simplest if the hardware state hasn't changed since
the suspend() was called, but that can't always be guaranteed.
Drivers must also be prepared to notice that the device has been removed
while the system was powered off, whenever that's physically possible.
PCMCIA, MMC, USB, Firewire, SCSI, and even IDE are common examples of busses
where common Linux platforms will see such removal. Details of how drivers
will notice and handle such removals are currently bus-specific, and often
involve a separate thread.
Note that the bus-specific runtime PM wakeup mechanism can exist, and might
be defined to share some of the same driver code as for system wakeup. For
example, a bus-specific device driver's resume() method might be used there,
so it wouldn't only be called from bus.resume() during system-wide wakeup.
See bus-specific information about how runtime wakeup events are handled.
System Devices
--------------
System devices follow a slightly different API, which can be found in
include/linux/sysdev.h
drivers/base/sys.c
System devices will only be suspended with interrupts disabled, and after
all other devices have been suspended. On resume, they will be resumed
before any other devices, and also with interrupts disabled.
That is, IRQs are disabled, the suspend_late() phase begins, then the
sysdev_driver.suspend() phase, and the system enters a sleep state. Then
the sysdev_driver.resume() phase begins, followed by the resume_early()
phase, after which IRQs are enabled.
Code to actually enter and exit the system-wide low power state sometimes
involves hardware details that are only known to the boot firmware, and
may leave a CPU running software (from SRAM or flash memory) that monitors
the system and manages its wakeup sequence.
For details refer to Documentation/power/notifiers.txt.
Runtime Power Management
@ -407,82 +585,23 @@ running. This feature is useful for devices that are not being used, and
can offer significant power savings on a running system. These devices
often support a range of runtime power states, which might use names such
as "off", "sleep", "idle", "active", and so on. Those states will in some
cases (like PCI) be partially constrained by a bus the device uses, and will
cases (like PCI) be partially constrained by the bus the device uses, and will
usually include hardware states that are also used in system sleep states.
However, note that if a driver puts a device into a runtime low power state
and the system then goes into a system-wide sleep state, it normally ought
to resume into that runtime low power state rather than "full on". Such
distinctions would be part of the driver-internal state machine for that
hardware; the whole point of runtime power management is to be sure that
drivers are decoupled in that way from the state machine governing phases
of the system-wide power/sleep state transitions.
A system-wide power transition can be started while some devices are in low
power states due to runtime power management. The system sleep PM callbacks
should recognize such situations and react to them appropriately, but the
necessary actions are subsystem-specific.
In some cases the decision may be made at the subsystem level while in other
cases the device driver may be left to decide. In some cases it may be
desirable to leave a suspended device in that state during a system-wide power
transition, but in other cases the device must be put back into the full-power
state temporarily, for example so that its system wakeup capability can be
disabled. This all depends on the hardware and the design of the subsystem and
device driver in question.
Power Saving Techniques
-----------------------
Normally runtime power management is handled by the drivers without specific
userspace or kernel intervention, by device-aware use of techniques like:
Using information provided by other system layers
- stay deeply "off" except between open() and close()
- if transceiver/PHY indicates "nobody connected", stay "off"
- application protocols may include power commands or hints
Using fewer CPU cycles
- using DMA instead of PIO
- removing timers, or making them lower frequency
- shortening "hot" code paths
- eliminating cache misses
- (sometimes) offloading work to device firmware
Reducing other resource costs
- gating off unused clocks in software (or hardware)
- switching off unused power supplies
- eliminating (or delaying/merging) IRQs
- tuning DMA to use word and/or burst modes
Using device-specific low power states
- using lower voltages
- avoiding needless DMA transfers
Read your hardware documentation carefully to see the opportunities that
may be available. If you can, measure the actual power usage and check
it against the budget established for your project.
Examples: USB hosts, system timer, system CPU
----------------------------------------------
USB host controllers make interesting, if complex, examples. In many cases
these have no work to do: no USB devices are connected, or all of them are
in the USB "suspend" state. Linux host controller drivers can then disable
periodic DMA transfers that would otherwise be a constant power drain on the
memory subsystem, and enter a suspend state. In power-aware controllers,
entering that suspend state may disable the clock used with USB signaling,
saving a certain amount of power.
The controller will be woken from that state (with an IRQ) by changes to the
signal state on the data lines of a given port, for example by an existing
peripheral requesting "remote wakeup" or by plugging a new peripheral. The
same wakeup mechanism usually works from "standby" sleep states, and on some
systems also from "suspend to RAM" (or even "suspend to disk") states.
(Except that ACPI may be involved instead of normal IRQs, on some hardware.)
System devices like timers and CPUs may have special roles in the platform
power management scheme. For example, system timers using a "dynamic tick"
approach don't just save CPU cycles (by eliminating needless timer IRQs),
but they may also open the door to using lower power CPU "idle" states that
cost more than a jiffie to enter and exit. On x86 systems these are states
like "C3"; note that periodic DMA transfers from a USB host controller will
also prevent entry to a C3 state, much like a periodic timer IRQ.
That kind of runtime mechanism interaction is common. "System On Chip" (SOC)
processors often have low power idle modes that can't be entered unless
certain medium-speed clocks (often 12 or 48 MHz) are gated off. When the
drivers gate those clocks effectively, then the system idle task may be able
to use the lower power idle modes and thereby increase battery life.
If the CPU can have a "cpufreq" driver, there also may be opportunities
to shift to lower voltage settings and reduce the power cost of executing
a given number of instructions. (Without voltage adjustment, it's rare
for cpufreq to save much power; the cost-per-instruction must go down.)
During system-wide resume from a sleep state it's best to put devices into the
full-power state, as explained in Documentation/power/runtime_pm.txt. Refer to
that document for more information regarding this particular issue as well as
for information on the device runtime power management framework in general.

48
Documentation/power/pm_qos_interface.txt
View File

@ -18,44 +18,46 @@ and pm_qos_params.h. This is done because having the available parameters
being runtime configurable or changeable from a driver was seen as too easy to
abuse.
For each parameter a list of performance requirements is maintained along with
For each parameter a list of performance requests is maintained along with
an aggregated target value. The aggregated target value is updated with
changes to the requirement list or elements of the list. Typically the
aggregated target value is simply the max or min of the requirement values held
changes to the request list or elements of the list. Typically the
aggregated target value is simply the max or min of the request values held
in the parameter list elements.
From kernel mode the use of this interface is simple:
pm_qos_add_requirement(param_id, name, target_value):
Will insert a named element in the list for that identified PM_QOS parameter
with the target value. Upon change to this list the new target is recomputed
and any registered notifiers are called only if the target value is now
different.
pm_qos_update_requirement(param_id, name, new_target_value):
Will search the list identified by the param_id for the named list element and
then update its target value, calling the notification tree if the aggregated
target is changed. with that name is already registered.
handle = pm_qos_add_request(param_class, target_value):
Will insert an element into the list for that identified PM_QOS class with the
target value. Upon change to this list the new target is recomputed and any
registered notifiers are called only if the target value is now different.
Clients of pm_qos need to save the returned handle.
pm_qos_remove_requirement(param_id, name):
Will search the identified list for the named element and remove it, after
removal it will update the aggregate target and call the notification tree if
the target was changed as a result of removing the named requirement.
void pm_qos_update_request(handle, new_target_value):
Will update the list element pointed to by the handle with the new target value
and recompute the new aggregated target, calling the notification tree if the
target is changed.
void pm_qos_remove_request(handle):
Will remove the element. After removal it will update the aggregate target and
call the notification tree if the target was changed as a result of removing
the request.
From user mode:
Only processes can register a pm_qos requirement. To provide for automatic
cleanup for process the interface requires the process to register its
parameter requirements in the following way:
Only processes can register a pm_qos request. To provide for automatic
cleanup of a process, the interface requires the process to register its
parameter requests in the following way:
To register the default pm_qos target for the specific parameter, the process
must open one of /dev/[cpu_dma_latency, network_latency, network_throughput]
As long as the device node is held open that process has a registered
requirement on the parameter. The name of the requirement is "process_<PID>"
derived from the current->pid from within the open system call.
request on the parameter.
To change the requested target value the process needs to write a s32 value to
the open device node. This translates to a pm_qos_update_requirement call.
To change the requested target value the process needs to write an s32 value to
the open device node. Alternatively the user mode program could write a hex
string for the value using 10 char long format e.g. "0x12345678". This
translates to a pm_qos_update_request call.
To remove the user mode request for a target value simply close the device
node.

4
Documentation/power/userland-swsusp.txt
View File

@ -24,6 +24,10 @@ assumed to be in the resume mode. The device cannot be open for simultaneous
reading and writing. It is also impossible to have the device open more than
once at a time.
Even opening the device has side effects. Data structures are
allocated, and PM_HIBERNATION_PREPARE / PM_RESTORE_PREPARE chains are
called.
The ioctl() commands recognized by the device are:
SNAPSHOT_FREEZE - freeze user space processes (the current process is

2
drivers/acpi/processor_idle.c
View File

@ -698,7 +698,7 @@ static int acpi_processor_power_seq_show(struct seq_file *seq, void *offset)
"max_cstate: C%d\n"
"maximum allowed latency: %d usec\n",
pr->power.state ? pr->power.state - pr->power.states : 0,
max_cstate, pm_qos_requirement(PM_QOS_CPU_DMA_LATENCY));
max_cstate, pm_qos_request(PM_QOS_CPU_DMA_LATENCY));
seq_puts(seq, "states:\n");

6
drivers/base/platform.c
View File

@ -967,17 +967,17 @@ static int platform_pm_restore_noirq(struct device *dev)
int __weak platform_pm_runtime_suspend(struct device *dev)
{
return -ENOSYS;
return pm_generic_runtime_suspend(dev);
};
int __weak platform_pm_runtime_resume(struct device *dev)
{
return -ENOSYS;
return pm_generic_runtime_resume(dev);
};
int __weak platform_pm_runtime_idle(struct device *dev)
{
return -ENOSYS;
return pm_generic_runtime_idle(dev);
};
#else /* !CONFIG_PM_RUNTIME */

10
drivers/base/power/runtime.c
View File

@ -229,14 +229,16 @@ int __pm_runtime_suspend(struct device *dev, bool from_wq)
if (retval) {
dev->power.runtime_status = RPM_ACTIVE;
pm_runtime_cancel_pending(dev);
if (retval == -EAGAIN || retval == -EBUSY) {
notify = true;
if (dev->power.timer_expires == 0)
notify = true;
dev->power.runtime_error = 0;
} else {
pm_runtime_cancel_pending(dev);
}
} else {
dev->power.runtime_status = RPM_SUSPENDED;
pm_runtime_deactivate_timer(dev);
if (dev->parent) {
parent = dev->parent;
@ -659,8 +661,6 @@ int pm_schedule_suspend(struct device *dev, unsigned int delay)
if (dev->power.runtime_status == RPM_SUSPENDED)
retval = 1;
else if (dev->power.runtime_status == RPM_SUSPENDING)
retval = -EINPROGRESS;
else if (atomic_read(&dev->power.usage_count) > 0
|| dev->power.disable_depth > 0)
retval = -EAGAIN;

65
drivers/base/power/sysfs.c
View File

@ -5,6 +5,7 @@
#include <linux/device.h>
#include <linux/string.h>
#include <linux/pm_runtime.h>
#include <asm/atomic.h>
#include "power.h"
/*
@ -143,7 +144,59 @@ wake_store(struct device * dev, struct device_attribute *attr,
static DEVICE_ATTR(wakeup, 0644, wake_show, wake_store);
#ifdef CONFIG_PM_SLEEP_ADVANCED_DEBUG
#ifdef CONFIG_PM_ADVANCED_DEBUG
#ifdef CONFIG_PM_RUNTIME
static ssize_t rtpm_usagecount_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sprintf(buf, "%d\n", atomic_read(&dev->power.usage_count));
}
static ssize_t rtpm_children_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sprintf(buf, "%d\n", dev->power.ignore_children ?
0 : atomic_read(&dev->power.child_count));
}
static ssize_t rtpm_enabled_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
if ((dev->power.disable_depth) && (dev->power.runtime_auto == false))
return sprintf(buf, "disabled & forbidden\n");
else if (dev->power.disable_depth)
return sprintf(buf, "disabled\n");
else if (dev->power.runtime_auto == false)
return sprintf(buf, "forbidden\n");
return sprintf(buf, "enabled\n");
}
static ssize_t rtpm_status_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
if (dev->power.runtime_error)
return sprintf(buf, "error\n");
switch (dev->power.runtime_status) {
case RPM_SUSPENDED:
return sprintf(buf, "suspended\n");
case RPM_SUSPENDING:
return sprintf(buf, "suspending\n");
case RPM_RESUMING:
return sprintf(buf, "resuming\n");
case RPM_ACTIVE:
return sprintf(buf, "active\n");
}
return -EIO;
}
static DEVICE_ATTR(runtime_usage, 0444, rtpm_usagecount_show, NULL);
static DEVICE_ATTR(runtime_active_kids, 0444, rtpm_children_show, NULL);
static DEVICE_ATTR(runtime_status, 0444, rtpm_status_show, NULL);
static DEVICE_ATTR(runtime_enabled, 0444, rtpm_enabled_show, NULL);
#endif
static ssize_t async_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
@ -170,15 +223,21 @@ static ssize_t async_store(struct device *dev, struct device_attribute *attr,
}
static DEVICE_ATTR(async, 0644, async_show, async_store);
#endif /* CONFIG_PM_SLEEP_ADVANCED_DEBUG */
#endif /* CONFIG_PM_ADVANCED_DEBUG */
static struct attribute * power_attrs[] = {
#ifdef CONFIG_PM_RUNTIME
&dev_attr_control.attr,
#endif
&dev_attr_wakeup.attr,
#ifdef CONFIG_PM_SLEEP_ADVANCED_DEBUG
#ifdef CONFIG_PM_ADVANCED_DEBUG
&dev_attr_async.attr,
#ifdef CONFIG_PM_RUNTIME
&dev_attr_runtime_usage.attr,
&dev_attr_runtime_active_kids.attr,
&dev_attr_runtime_status.attr,
&dev_attr_runtime_enabled.attr,
#endif
#endif
NULL,
};

2
drivers/cpuidle/governors/ladder.c
View File

@ -67,7 +67,7 @@ static int ladder_select_state(struct cpuidle_device *dev)
struct ladder_device *ldev = &__get_cpu_var(ladder_devices);
struct ladder_device_state *last_state;
int last_residency, last_idx = ldev->last_state_idx;
int latency_req = pm_qos_requirement(PM_QOS_CPU_DMA_LATENCY);
int latency_req = pm_qos_request(PM_QOS_CPU_DMA_LATENCY);
/* Special case when user has set very strict latency requirement */
if (unlikely(latency_req == 0)) {

2
drivers/cpuidle/governors/menu.c
View File

@ -182,7 +182,7 @@ static u64 div_round64(u64 dividend, u32 divisor)
static int menu_select(struct cpuidle_device *dev)
{
struct menu_device *data = &__get_cpu_var(menu_devices);
int latency_req = pm_qos_requirement(PM_QOS_CPU_DMA_LATENCY);
int latency_req = pm_qos_request(PM_QOS_CPU_DMA_LATENCY);
int i;
int multiplier;

192
drivers/i2c/i2c-core.c
View File

@ -159,82 +159,8 @@ static void i2c_device_shutdown(struct device *dev)
driver->shutdown(client);
}
#ifdef CONFIG_SUSPEND
static int i2c_device_pm_suspend(struct device *dev)
{
const struct dev_pm_ops *pm;
if (!dev->driver)
return 0;
pm = dev->driver->pm;
if (!pm || !pm->suspend)
return 0;
return pm->suspend(dev);
}
static int i2c_device_pm_resume(struct device *dev)
{
const struct dev_pm_ops *pm;
if (!dev->driver)
return 0;
pm = dev->driver->pm;
if (!pm || !pm->resume)
return 0;
return pm->resume(dev);
}
#else
#define i2c_device_pm_suspend NULL
#define i2c_device_pm_resume NULL
#endif
#ifdef CONFIG_PM_RUNTIME
static int i2c_device_runtime_suspend(struct device *dev)
{
const struct dev_pm_ops *pm;
if (!dev->driver)
return 0;
pm = dev->driver->pm;
if (!pm || !pm->runtime_suspend)
return 0;
return pm->runtime_suspend(dev);
}
static int i2c_device_runtime_resume(struct device *dev)
{
const struct dev_pm_ops *pm;
if (!dev->driver)
return 0;
pm = dev->driver->pm;
if (!pm || !pm->runtime_resume)
return 0;
return pm->runtime_resume(dev);
}
static int i2c_device_runtime_idle(struct device *dev)
{
const struct dev_pm_ops *pm = NULL;
int ret;
if (dev->driver)
pm = dev->driver->pm;
if (pm && pm->runtime_idle) {
ret = pm->runtime_idle(dev);
if (ret)
return ret;
}
return pm_runtime_suspend(dev);
}
#else
#define i2c_device_runtime_suspend NULL
#define i2c_device_runtime_resume NULL
#define i2c_device_runtime_idle NULL
#endif
static int i2c_device_suspend(struct device *dev, pm_message_t mesg)
#ifdef CONFIG_PM_SLEEP
static int i2c_legacy_suspend(struct device *dev, pm_message_t mesg)
{
struct i2c_client *client = i2c_verify_client(dev);
struct i2c_driver *driver;
@ -247,7 +173,7 @@ static int i2c_device_suspend(struct device *dev, pm_message_t mesg)
return driver->suspend(client, mesg);
}
static int i2c_device_resume(struct device *dev)
static int i2c_legacy_resume(struct device *dev)
{
struct i2c_client *client = i2c_verify_client(dev);
struct i2c_driver *driver;
@ -260,6 +186,104 @@ static int i2c_device_resume(struct device *dev)
return driver->resume(client);
}
static int i2c_device_pm_suspend(struct device *dev)
{
const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
if (pm_runtime_suspended(dev))
return 0;
if (pm)
return pm->suspend ? pm->suspend(dev) : 0;
return i2c_legacy_suspend(dev, PMSG_SUSPEND);
}
static int i2c_device_pm_resume(struct device *dev)
{
const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
int ret;
if (pm)
ret = pm->resume ? pm->resume(dev) : 0;
else
ret = i2c_legacy_resume(dev);
if (!ret) {
pm_runtime_disable(dev);
pm_runtime_set_active(dev);
pm_runtime_enable(dev);
}
return ret;
}
static int i2c_device_pm_freeze(struct device *dev)
{
const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
if (pm_runtime_suspended(dev))
return 0;
if (pm)
return pm->freeze ? pm->freeze(dev) : 0;
return i2c_legacy_suspend(dev, PMSG_FREEZE);
}
static int i2c_device_pm_thaw(struct device *dev)
{
const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
if (pm_runtime_suspended(dev))
return 0;
if (pm)
return pm->thaw ? pm->thaw(dev) : 0;
return i2c_legacy_resume(dev);
}
static int i2c_device_pm_poweroff(struct device *dev)
{
const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
if (pm_runtime_suspended(dev))
return 0;
if (pm)
return pm->poweroff ? pm->poweroff(dev) : 0;
return i2c_legacy_suspend(dev, PMSG_HIBERNATE);
}
static int i2c_device_pm_restore(struct device *dev)
{
const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
int ret;
if (pm)
ret = pm->restore ? pm->restore(dev) : 0;
else
ret = i2c_legacy_resume(dev);
if (!ret) {
pm_runtime_disable(dev);
pm_runtime_set_active(dev);
pm_runtime_enable(dev);
}
return ret;
}
#else /* !CONFIG_PM_SLEEP */
#define i2c_device_pm_suspend NULL
#define i2c_device_pm_resume NULL
#define i2c_device_pm_freeze NULL
#define i2c_device_pm_thaw NULL
#define i2c_device_pm_poweroff NULL
#define i2c_device_pm_restore NULL
#endif /* !CONFIG_PM_SLEEP */
static void i2c_client_dev_release(struct device *dev)
{
kfree(to_i2c_client(dev));
@ -301,9 +325,15 @@ static const struct attribute_group *i2c_dev_attr_groups[] = {
static const struct dev_pm_ops i2c_device_pm_ops = {
.suspend = i2c_device_pm_suspend,
.resume = i2c_device_pm_resume,
.runtime_suspend = i2c_device_runtime_suspend,
.runtime_resume = i2c_device_runtime_resume,
.runtime_idle = i2c_device_runtime_idle,
.freeze = i2c_device_pm_freeze,
.thaw = i2c_device_pm_thaw,
.poweroff = i2c_device_pm_poweroff,
.restore = i2c_device_pm_restore,
SET_RUNTIME_PM_OPS(
pm_generic_runtime_suspend,
pm_generic_runtime_resume,
pm_generic_runtime_idle
)
};
struct bus_type i2c_bus_type = {
@ -312,8 +342,6 @@ struct bus_type i2c_bus_type = {
.probe = i2c_device_probe,
.remove = i2c_device_remove,
.shutdown = i2c_device_shutdown,
.suspend = i2c_device_suspend,
.resume = i2c_device_resume,
.pm = &i2c_device_pm_ops,
};
EXPORT_SYMBOL_GPL(i2c_bus_type);

22
drivers/net/e1000e/netdev.c
View File

@ -2524,12 +2524,12 @@ static void e1000_configure_rx(struct e1000_adapter *adapter)
* excessive C-state transition latencies result in
* dropped transactions.
*/
pm_qos_update_requirement(PM_QOS_CPU_DMA_LATENCY,
adapter->netdev->name, 55);
pm_qos_update_request(
adapter->netdev->pm_qos_req, 55);
} else {
pm_qos_update_requirement(PM_QOS_CPU_DMA_LATENCY,
adapter->netdev->name,
PM_QOS_DEFAULT_VALUE);
pm_qos_update_request(
adapter->netdev->pm_qos_req,
PM_QOS_DEFAULT_VALUE);
}
}
@ -2824,8 +2824,8 @@ int e1000e_up(struct e1000_adapter *adapter)
/* DMA latency requirement to workaround early-receive/jumbo issue */
if (adapter->flags & FLAG_HAS_ERT)
pm_qos_add_requirement(PM_QOS_CPU_DMA_LATENCY,
adapter->netdev->name,
adapter->netdev->pm_qos_req =
pm_qos_add_request(PM_QOS_CPU_DMA_LATENCY,
PM_QOS_DEFAULT_VALUE);
/* hardware has been reset, we need to reload some things */
@ -2887,9 +2887,11 @@ void e1000e_down(struct e1000_adapter *adapter)
e1000_clean_tx_ring(adapter);
e1000_clean_rx_ring(adapter);
if (adapter->flags & FLAG_HAS_ERT)
pm_qos_remove_requirement(PM_QOS_CPU_DMA_LATENCY,
adapter->netdev->name);
if (adapter->flags & FLAG_HAS_ERT) {
pm_qos_remove_request(
adapter->netdev->pm_qos_req);
adapter->netdev->pm_qos_req = NULL;
}
/*
* TODO: for power management, we could drop the link and

6
drivers/net/igbvf/netdev.c
View File

@ -48,6 +48,7 @@
#define DRV_VERSION "1.0.0-k0"
char igbvf_driver_name[] = "igbvf";
const char igbvf_driver_version[] = DRV_VERSION;
struct pm_qos_request_list *igbvf_driver_pm_qos_req;
static const char igbvf_driver_string[] =
"Intel(R) Virtual Function Network Driver";
static const char igbvf_copyright[] = "Copyright (c) 2009 Intel Corporation.";
@ -2899,7 +2900,7 @@ static int __init igbvf_init_module(void)
printk(KERN_INFO "%s\n", igbvf_copyright);
ret = pci_register_driver(&igbvf_driver);
pm_qos_add_requirement(PM_QOS_CPU_DMA_LATENCY, igbvf_driver_name,
igbvf_driver_pm_qos_req = pm_qos_add_request(PM_QOS_CPU_DMA_LATENCY,
PM_QOS_DEFAULT_VALUE);
return ret;
@ -2915,7 +2916,8 @@ module_init(igbvf_init_module);
static void __exit igbvf_exit_module(void)
{
pci_unregister_driver(&igbvf_driver);
pm_qos_remove_requirement(PM_QOS_CPU_DMA_LATENCY, igbvf_driver_name);
pm_qos_remove_request(igbvf_driver_pm_qos_req);
igbvf_driver_pm_qos_req = NULL;
}
module_exit(igbvf_exit_module);

11
drivers/net/wireless/ipw2x00/ipw2100.c
View File

@ -174,6 +174,8 @@ that only one external action is invoked at a time.
#define DRV_DESCRIPTION "Intel(R) PRO/Wireless 2100 Network Driver"
#define DRV_COPYRIGHT "Copyright(c) 2003-2006 Intel Corporation"
struct pm_qos_request_list *ipw2100_pm_qos_req;
/* Debugging stuff */
#ifdef CONFIG_IPW2100_DEBUG
#define IPW2100_RX_DEBUG /* Reception debugging */
@ -1739,7 +1741,7 @@ static int ipw2100_up(struct ipw2100_priv *priv, int deferred)
/* the ipw2100 hardware really doesn't want power management delays
* longer than 175usec
*/
pm_qos_update_requirement(PM_QOS_CPU_DMA_LATENCY, "ipw2100", 175);
pm_qos_update_request(ipw2100_pm_qos_req, 175);
/* If the interrupt is enabled, turn it off... */
spin_lock_irqsave(&priv->low_lock, flags);
@ -1887,8 +1889,7 @@ static void ipw2100_down(struct ipw2100_priv *priv)
ipw2100_disable_interrupts(priv);
spin_unlock_irqrestore(&priv->low_lock, flags);
pm_qos_update_requirement(PM_QOS_CPU_DMA_LATENCY, "ipw2100",
PM_QOS_DEFAULT_VALUE);
pm_qos_update_request(ipw2100_pm_qos_req, PM_QOS_DEFAULT_VALUE);
/* We have to signal any supplicant if we are disassociating */
if (associated)
@ -6669,7 +6670,7 @@ static int __init ipw2100_init(void)
if (ret)
goto out;
pm_qos_add_requirement(PM_QOS_CPU_DMA_LATENCY, "ipw2100",
ipw2100_pm_qos_req = pm_qos_add_request(PM_QOS_CPU_DMA_LATENCY,
PM_QOS_DEFAULT_VALUE);
#ifdef CONFIG_IPW2100_DEBUG
ipw2100_debug_level = debug;
@ -6692,7 +6693,7 @@ static void __exit ipw2100_exit(void)
&driver_attr_debug_level);
#endif
pci_unregister_driver(&ipw2100_pci_driver);
pm_qos_remove_requirement(PM_QOS_CPU_DMA_LATENCY, "ipw2100");
pm_qos_remove_request(ipw2100_pm_qos_req);
}
module_init(ipw2100_init);

35
fs/libfs.c
View File

@ -546,6 +546,40 @@ ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos,
return count;
}
/**
* simple_write_to_buffer - copy data from user space to the buffer
* @to: the buffer to write to
* @available: the size of the buffer
* @ppos: the current position in the buffer
* @from: the user space buffer to read from
* @count: the maximum number of bytes to read
*
* The simple_write_to_buffer() function reads up to @count bytes from the user
* space address starting at @from into the buffer @to at offset @ppos.
*
* On success, the number of bytes written is returned and the offset @ppos is
* advanced by this number, or negative value is returned on error.
**/
ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos,
const void __user *from, size_t count)
{
loff_t pos = *ppos;
size_t res;
if (pos < 0)
return -EINVAL;
if (pos >= available || !count)
return 0;
if (count > available - pos)
count = available - pos;
res = copy_from_user(to + pos, from, count);
if (res == count)
return -EFAULT;
count -= res;
*ppos = pos + count;
return count;
}
/**
* memory_read_from_buffer - copy data from the buffer
* @to: the kernel space buffer to read to
@ -864,6 +898,7 @@ EXPORT_SYMBOL(simple_statfs);
EXPORT_SYMBOL(simple_sync_file);
EXPORT_SYMBOL(simple_unlink);
EXPORT_SYMBOL(simple_read_from_buffer);
EXPORT_SYMBOL(simple_write_to_buffer);
EXPORT_SYMBOL(memory_read_from_buffer);
EXPORT_SYMBOL(simple_transaction_set);
EXPORT_SYMBOL(simple_transaction_get);

2
include/linux/fs.h
View File

@ -2362,6 +2362,8 @@ extern void simple_release_fs(struct vfsmount **mount, int *count);
extern ssize_t simple_read_from_buffer(void __user *to, size_t count,
loff_t *ppos, const void *from, size_t available);
extern ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos,
const void __user *from, size_t count);
extern int simple_fsync(struct file *, struct dentry *, int);

4
include/linux/netdevice.h
View File

@ -31,6 +31,7 @@
#include <linux/if_link.h>
#ifdef __KERNEL__
#include <linux/pm_qos_params.h>
#include <linux/timer.h>
#include <linux/delay.h>
#include <linux/mm.h>
@ -711,6 +712,9 @@ struct net_device {
* the interface.
*/
char name[IFNAMSIZ];
struct pm_qos_request_list *pm_qos_req;
/* device name hash chain */
struct hlist_node name_hlist;
/* snmp alias */

14
include/linux/pm_qos_params.h
View File

@ -14,12 +14,14 @@
#define PM_QOS_NUM_CLASSES 4
#define PM_QOS_DEFAULT_VALUE -1
int pm_qos_add_requirement(int qos, char *name, s32 value);
int pm_qos_update_requirement(int qos, char *name, s32 new_value);
void pm_qos_remove_requirement(int qos, char *name);
struct pm_qos_request_list;
int pm_qos_requirement(int qos);
struct pm_qos_request_list *pm_qos_add_request(int pm_qos_class, s32 value);
void pm_qos_update_request(struct pm_qos_request_list *pm_qos_req,
s32 new_value);
void pm_qos_remove_request(struct pm_qos_request_list *pm_qos_req);
int pm_qos_add_notifier(int qos, struct notifier_block *notifier);
int pm_qos_remove_notifier(int qos, struct notifier_block *notifier);
int pm_qos_request(int pm_qos_class);
int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier);
int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier);

7
include/linux/pm_runtime.h
View File

@ -30,6 +30,9 @@ extern void pm_runtime_enable(struct device *dev);
extern void __pm_runtime_disable(struct device *dev, bool check_resume);
extern void pm_runtime_allow(struct device *dev);
extern void pm_runtime_forbid(struct device *dev);
extern int pm_generic_runtime_idle(struct device *dev);
extern int pm_generic_runtime_suspend(struct device *dev);
extern int pm_generic_runtime_resume(struct device *dev);
static inline bool pm_children_suspended(struct device *dev)
{
@ -96,6 +99,10 @@ static inline bool device_run_wake(struct device *dev) { return false; }
static inline void device_set_run_wake(struct device *dev, bool enable) {}
static inline bool pm_runtime_suspended(struct device *dev) { return false; }
static inline int pm_generic_runtime_idle(struct device *dev) { return 0; }
static inline int pm_generic_runtime_suspend(struct device *dev) { return 0; }
static inline int pm_generic_runtime_resume(struct device *dev) { return 0; }
#endif /* !CONFIG_PM_RUNTIME */
static inline int pm_runtime_get(struct device *dev)

38
include/linux/pm_wakeup.h
View File

@ -25,32 +25,34 @@
# error "please don't include this file directly"
#endif
#include <linux/types.h>
#ifdef CONFIG_PM
/* changes to device_may_wakeup take effect on the next pm state change.
* by default, devices should wakeup if they can.
*/
static inline void device_init_wakeup(struct device *dev, int val)
static inline void device_init_wakeup(struct device *dev, bool val)
{
dev->power.can_wakeup = dev->power.should_wakeup = !!val;
dev->power.can_wakeup = dev->power.should_wakeup = val;
}
static inline void device_set_wakeup_capable(struct device *dev, int val)
static inline void device_set_wakeup_capable(struct device *dev, bool capable)
{
dev->power.can_wakeup = !!val;
dev->power.can_wakeup = capable;
}
static inline int device_can_wakeup(struct device *dev)
static inline bool device_can_wakeup(struct device *dev)
{
return dev->power.can_wakeup;
}
static inline void device_set_wakeup_enable(struct device *dev, int val)
static inline void device_set_wakeup_enable(struct device *dev, bool enable)
{
dev->power.should_wakeup = !!val;
dev->power.should_wakeup = enable;
}
static inline int device_may_wakeup(struct device *dev)
static inline bool device_may_wakeup(struct device *dev)
{
return dev->power.can_wakeup && dev->power.should_wakeup;
}
@ -58,20 +60,28 @@ static inline int device_may_wakeup(struct device *dev)
#else /* !CONFIG_PM */
/* For some reason the next two routines work even without CONFIG_PM */
static inline void device_init_wakeup(struct device *dev, int val)
static inline void device_init_wakeup(struct device *dev, bool val)
{
dev->power.can_wakeup = !!val;
dev->power.can_wakeup = val;
}
static inline void device_set_wakeup_capable(struct device *dev, int val) { }
static inline void device_set_wakeup_capable(struct device *dev, bool capable)
{
}
static inline int device_can_wakeup(struct device *dev)
static inline bool device_can_wakeup(struct device *dev)
{
return dev->power.can_wakeup;
}
#define device_set_wakeup_enable(dev, val) do {} while (0)
#define device_may_wakeup(dev) 0
static inline void device_set_wakeup_enable(struct device *dev, bool enable)
{
}
static inline bool device_may_wakeup(struct device *dev)
{
return false;
}
#endif /* !CONFIG_PM */

3
include/sound/pcm.h
View File

@ -29,6 +29,7 @@
#include <linux/poll.h>
#include <linux/mm.h>
#include <linux/bitops.h>
#include <linux/pm_qos_params.h>
#define snd_pcm_substream_chip(substream) ((substream)->private_data)
#define snd_pcm_chip(pcm) ((pcm)->private_data)
@ -365,7 +366,7 @@ struct snd_pcm_substream {
int number;
char name[32]; /* substream name */
int stream; /* stream (direction) */
char latency_id[20]; /* latency identifier */
struct pm_qos_request_list *latency_pm_qos_req; /* pm_qos request */
size_t buffer_bytes_max; /* limit ring buffer size */
struct snd_dma_buffer dma_buffer;
unsigned int dma_buf_id;

21
kernel/cgroup_freezer.c
View File

@ -89,10 +89,10 @@ struct cgroup_subsys freezer_subsys;
/* Locks taken and their ordering
* ------------------------------
* css_set_lock
* cgroup_mutex (AKA cgroup_lock)
* task->alloc_lock (AKA task_lock)
* freezer->lock
* css_set_lock
* task->alloc_lock (AKA task_lock)
* task->sighand->siglock
*
* cgroup code forces css_set_lock to be taken before task->alloc_lock
@ -100,33 +100,38 @@ struct cgroup_subsys freezer_subsys;
* freezer_create(), freezer_destroy():
* cgroup_mutex [ by cgroup core ]
*
* can_attach():
* cgroup_mutex
* freezer_can_attach():
* cgroup_mutex (held by caller of can_attach)
*
* cgroup_frozen():
* cgroup_freezing_or_frozen():
* task->alloc_lock (to get task's cgroup)
*
* freezer_fork() (preserving fork() performance means can't take cgroup_mutex):
* task->alloc_lock (to get task's cgroup)
* freezer->lock
* sighand->siglock (if the cgroup is freezing)
*
* freezer_read():
* cgroup_mutex
* freezer->lock
* write_lock css_set_lock (cgroup iterator start)
* task->alloc_lock
* read_lock css_set_lock (cgroup iterator start)
*
* freezer_write() (freeze):
* cgroup_mutex
* freezer->lock
* write_lock css_set_lock (cgroup iterator start)
* task->alloc_lock
* read_lock css_set_lock (cgroup iterator start)
* sighand->siglock
* sighand->siglock (fake signal delivery inside freeze_task())
*
* freezer_write() (unfreeze):
* cgroup_mutex
* freezer->lock
* write_lock css_set_lock (cgroup iterator start)
* task->alloc_lock
* read_lock css_set_lock (cgroup iterator start)
* task->alloc_lock (to prevent races with freeze_task())
* task->alloc_lock (inside thaw_process(), prevents race with refrigerator())
* sighand->siglock
*/
static struct cgroup_subsys_state *freezer_create(struct cgroup_subsys *ss,

216
kernel/pm_qos_params.c
View File

@ -2,7 +2,7 @@
* This module exposes the interface to kernel space for specifying
* QoS dependencies. It provides infrastructure for registration of:
*
* Dependents on a QoS value : register requirements
* Dependents on a QoS value : register requests
* Watchers of QoS value : get notified when target QoS value changes
*
* This QoS design is best effort based. Dependents register their QoS needs.
@ -14,19 +14,21 @@
* timeout: usec <-- currently not used.
* throughput: kbs (kilo byte / sec)
*
* There are lists of pm_qos_objects each one wrapping requirements, notifiers
* There are lists of pm_qos_objects each one wrapping requests, notifiers
*
* User mode requirements on a QOS parameter register themselves to the
* User mode requests on a QOS parameter register themselves to the
* subsystem by opening the device node /dev/... and writing there request to
* the node. As long as the process holds a file handle open to the node the
* client continues to be accounted for. Upon file release the usermode
* requirement is removed and a new qos target is computed. This way when the
* requirement that the application has is cleaned up when closes the file
* request is removed and a new qos target is computed. This way when the
* request that the application has is cleaned up when closes the file
* pointer or exits the pm_qos_object will get an opportunity to clean up.
*
* Mark Gross <mgross@linux.intel.com>
*/
/*#define DEBUG*/
#include <linux/pm_qos_params.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
@ -42,25 +44,25 @@
#include <linux/uaccess.h>
/*
* locking rule: all changes to requirements or notifiers lists
* locking rule: all changes to requests or notifiers lists
* or pm_qos_object list and pm_qos_objects need to happen with pm_qos_lock
* held, taken with _irqsave. One lock to rule them all
*/
struct requirement_list {
struct pm_qos_request_list {
struct list_head list;
union {
s32 value;
s32 usec;
s32 kbps;
};
char *name;
int pm_qos_class;
};
static s32 max_compare(s32 v1, s32 v2);
static s32 min_compare(s32 v1, s32 v2);
struct pm_qos_object {
struct requirement_list requirements;
struct pm_qos_request_list requests;
struct blocking_notifier_head *notifiers;
struct miscdevice pm_qos_power_miscdev;
char *name;
@ -72,7 +74,7 @@ struct pm_qos_object {
static struct pm_qos_object null_pm_qos;
static BLOCKING_NOTIFIER_HEAD(cpu_dma_lat_notifier);
static struct pm_qos_object cpu_dma_pm_qos = {
.requirements = {LIST_HEAD_INIT(cpu_dma_pm_qos.requirements.list)},
.requests = {LIST_HEAD_INIT(cpu_dma_pm_qos.requests.list)},
.notifiers = &cpu_dma_lat_notifier,
.name = "cpu_dma_latency",
.default_value = 2000 * USEC_PER_SEC,
@ -82,7 +84,7 @@ static struct pm_qos_object cpu_dma_pm_qos = {
static BLOCKING_NOTIFIER_HEAD(network_lat_notifier);
static struct pm_qos_object network_lat_pm_qos = {
.requirements = {LIST_HEAD_INIT(network_lat_pm_qos.requirements.list)},
.requests = {LIST_HEAD_INIT(network_lat_pm_qos.requests.list)},
.notifiers = &network_lat_notifier,
.name = "network_latency",
.default_value = 2000 * USEC_PER_SEC,
@ -93,8 +95,7 @@ static struct pm_qos_object network_lat_pm_qos = {
static BLOCKING_NOTIFIER_HEAD(network_throughput_notifier);
static struct pm_qos_object network_throughput_pm_qos = {
.requirements =
{LIST_HEAD_INIT(network_throughput_pm_qos.requirements.list)},
.requests = {LIST_HEAD_INIT(network_throughput_pm_qos.requests.list)},
.notifiers = &network_throughput_notifier,
.name = "network_throughput",
.default_value = 0,
@ -135,31 +136,34 @@ static s32 min_compare(s32 v1, s32 v2)
}
static void update_target(int target)
static void update_target(int pm_qos_class)
{
s32 extreme_value;
struct requirement_list *node;
struct pm_qos_request_list *node;
unsigned long flags;
int call_notifier = 0;
spin_lock_irqsave(&pm_qos_lock, flags);
extreme_value = pm_qos_array[target]->default_value;
extreme_value = pm_qos_array[pm_qos_class]->default_value;
list_for_each_entry(node,
&pm_qos_array[target]->requirements.list, list) {
extreme_value = pm_qos_array[target]->comparitor(
&pm_qos_array[pm_qos_class]->requests.list, list) {
extreme_value = pm_qos_array[pm_qos_class]->comparitor(
extreme_value, node->value);
}
if (atomic_read(&pm_qos_array[target]->target_value) != extreme_value) {
if (atomic_read(&pm_qos_array[pm_qos_class]->target_value) !=
extreme_value) {
call_notifier = 1;
atomic_set(&pm_qos_array[target]->target_value, extreme_value);
pr_debug(KERN_ERR "new target for qos %d is %d\n", target,
atomic_read(&pm_qos_array[target]->target_value));
atomic_set(&pm_qos_array[pm_qos_class]->target_value,
extreme_value);
pr_debug(KERN_ERR "new target for qos %d is %d\n", pm_qos_class,
atomic_read(&pm_qos_array[pm_qos_class]->target_value));
}
spin_unlock_irqrestore(&pm_qos_lock, flags);
if (call_notifier)
blocking_notifier_call_chain(pm_qos_array[target]->notifiers,
(unsigned long) extreme_value, NULL);
blocking_notifier_call_chain(
pm_qos_array[pm_qos_class]->notifiers,
(unsigned long) extreme_value, NULL);
}
static int register_pm_qos_misc(struct pm_qos_object *qos)
@ -185,125 +189,112 @@ static int find_pm_qos_object_by_minor(int minor)
}
/**
* pm_qos_requirement - returns current system wide qos expectation
* pm_qos_request - returns current system wide qos expectation
* @pm_qos_class: identification of which qos value is requested
*
* This function returns the current target value in an atomic manner.
*/
int pm_qos_requirement(int pm_qos_class)
int pm_qos_request(int pm_qos_class)
{
return atomic_read(&pm_qos_array[pm_qos_class]->target_value);
}
EXPORT_SYMBOL_GPL(pm_qos_requirement);
EXPORT_SYMBOL_GPL(pm_qos_request);
/**
* pm_qos_add_requirement - inserts new qos request into the list
* pm_qos_add_request - inserts new qos request into the list
* @pm_qos_class: identifies which list of qos request to us
* @name: identifies the request
* @value: defines the qos request
*
* This function inserts a new entry in the pm_qos_class list of requested qos
* performance characteristics. It recomputes the aggregate QoS expectations
* for the pm_qos_class of parameters.
* for the pm_qos_class of parameters, and returns the pm_qos_request list
* element as a handle for use in updating and removal. Call needs to save
* this handle for later use.
*/
int pm_qos_add_requirement(int pm_qos_class, char *name, s32 value)
struct pm_qos_request_list *pm_qos_add_request(int pm_qos_class, s32 value)
{
struct requirement_list *dep;
struct pm_qos_request_list *dep;
unsigned long flags;
dep = kzalloc(sizeof(struct requirement_list), GFP_KERNEL);
dep = kzalloc(sizeof(struct pm_qos_request_list), GFP_KERNEL);
if (dep) {
if (value == PM_QOS_DEFAULT_VALUE)
dep->value = pm_qos_array[pm_qos_class]->default_value;
else
dep->value = value;
dep->name = kstrdup(name, GFP_KERNEL);
if (!dep->name)
goto cleanup;
dep->pm_qos_class = pm_qos_class;
spin_lock_irqsave(&pm_qos_lock, flags);
list_add(&dep->list,
&pm_qos_array[pm_qos_class]->requirements.list);
&pm_qos_array[pm_qos_class]->requests.list);
spin_unlock_irqrestore(&pm_qos_lock, flags);
update_target(pm_qos_class);
return 0;
}
cleanup:
kfree(dep);
return -ENOMEM;
return dep;
}
EXPORT_SYMBOL_GPL(pm_qos_add_requirement);
EXPORT_SYMBOL_GPL(pm_qos_add_request);
/**
* pm_qos_update_requirement - modifies an existing qos request
* @pm_qos_class: identifies which list of qos request to us
* @name: identifies the request
* pm_qos_update_request - modifies an existing qos request
* @pm_qos_req : handle to list element holding a pm_qos request to use
* @value: defines the qos request
*
* Updates an existing qos requirement for the pm_qos_class of parameters along
* Updates an existing qos request for the pm_qos_class of parameters along
* with updating the target pm_qos_class value.
*
* If the named request isn't in the list then no change is made.
* Attempts are made to make this code callable on hot code paths.
*/
int pm_qos_update_requirement(int pm_qos_class, char *name, s32 new_value)
void pm_qos_update_request(struct pm_qos_request_list *pm_qos_req,
s32 new_value)
{
unsigned long flags;
struct requirement_list *node;
int pending_update = 0;
s32 temp;
spin_lock_irqsave(&pm_qos_lock, flags);
list_for_each_entry(node,
&pm_qos_array[pm_qos_class]->requirements.list, list) {
if (strcmp(node->name, name) == 0) {
if (new_value == PM_QOS_DEFAULT_VALUE)
node->value =
pm_qos_array[pm_qos_class]->default_value;
else
node->value = new_value;
if (pm_qos_req) { /*guard against callers passing in null */
spin_lock_irqsave(&pm_qos_lock, flags);
if (new_value == PM_QOS_DEFAULT_VALUE)
temp = pm_qos_array[pm_qos_req->pm_qos_class]->default_value;
else
temp = new_value;
if (temp != pm_qos_req->value) {
pending_update = 1;
break;
pm_qos_req->value = temp;
}
spin_unlock_irqrestore(&pm_qos_lock, flags);
if (pending_update)
update_target(pm_qos_req->pm_qos_class);
}
spin_unlock_irqrestore(&pm_qos_lock, flags);
if (pending_update)
update_target(pm_qos_class);
return 0;
}
EXPORT_SYMBOL_GPL(pm_qos_update_requirement);
EXPORT_SYMBOL_GPL(pm_qos_update_request);
/**
* pm_qos_remove_requirement - modifies an existing qos request
* @pm_qos_class: identifies which list of qos request to us
* @name: identifies the request
* pm_qos_remove_request - modifies an existing qos request
* @pm_qos_req: handle to request list element
*
* Will remove named qos request from pm_qos_class list of parameters and
* recompute the current target value for the pm_qos_class.
* Will remove pm qos request from the list of requests and
* recompute the current target value for the pm_qos_class. Call this
* on slow code paths.
*/
void pm_qos_remove_requirement(int pm_qos_class, char *name)
void pm_qos_remove_request(struct pm_qos_request_list *pm_qos_req)
{
unsigned long flags;
struct requirement_list *node;
int pending_update = 0;
int qos_class;
if (pm_qos_req == NULL)
return;
/* silent return to keep pcm code cleaner */
qos_class = pm_qos_req->pm_qos_class;
spin_lock_irqsave(&pm_qos_lock, flags);
list_for_each_entry(node,
&pm_qos_array[pm_qos_class]->requirements.list, list) {
if (strcmp(node->name, name) == 0) {
kfree(node->name);
list_del(&node->list);
kfree(node);
pending_update = 1;
break;
}
}
list_del(&pm_qos_req->list);
kfree(pm_qos_req);
spin_unlock_irqrestore(&pm_qos_lock, flags);
if (pending_update)
update_target(pm_qos_class);
update_target(qos_class);
}
EXPORT_SYMBOL_GPL(pm_qos_remove_requirement);
EXPORT_SYMBOL_GPL(pm_qos_remove_request);
/**
* pm_qos_add_notifier - sets notification entry for changes to target value
@ -313,7 +304,7 @@ EXPORT_SYMBOL_GPL(pm_qos_remove_requirement);
* will register the notifier into a notification chain that gets called
* upon changes to the pm_qos_class target value.
*/
int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier)
int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier)
{
int retval;
@ -343,21 +334,16 @@ int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier)
}
EXPORT_SYMBOL_GPL(pm_qos_remove_notifier);
#define PID_NAME_LEN 32
static int pm_qos_power_open(struct inode *inode, struct file *filp)
{
int ret;
long pm_qos_class;
char name[PID_NAME_LEN];
pm_qos_class = find_pm_qos_object_by_minor(iminor(inode));
if (pm_qos_class >= 0) {
filp->private_data = (void *)pm_qos_class;
snprintf(name, PID_NAME_LEN, "process_%d", current->pid);
ret = pm_qos_add_requirement(pm_qos_class, name,
PM_QOS_DEFAULT_VALUE);
if (ret >= 0)
filp->private_data = (void *) pm_qos_add_request(pm_qos_class,
PM_QOS_DEFAULT_VALUE);
if (filp->private_data)
return 0;
}
return -EPERM;
@ -365,32 +351,40 @@ static int pm_qos_power_open(struct inode *inode, struct file *filp)
static int pm_qos_power_release(struct inode *inode, struct file *filp)
{
int pm_qos_class;
char name[PID_NAME_LEN];
struct pm_qos_request_list *req;
pm_qos_class = (long)filp->private_data;
snprintf(name, PID_NAME_LEN, "process_%d", current->pid);
pm_qos_remove_requirement(pm_qos_class, name);
req = (struct pm_qos_request_list *)filp->private_data;
pm_qos_remove_request(req);
return 0;
}
static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf,
size_t count, loff_t *f_pos)
{
s32 value;
int pm_qos_class;
char name[PID_NAME_LEN];
int x;
char ascii_value[11];
struct pm_qos_request_list *pm_qos_req;
pm_qos_class = (long)filp->private_data;
if (count != sizeof(s32))
if (count == sizeof(s32)) {
if (copy_from_user(&value, buf, sizeof(s32)))
return -EFAULT;
} else if (count == 11) { /* len('0x12345678/0') */
if (copy_from_user(ascii_value, buf, 11))
return -EFAULT;
x = sscanf(ascii_value, "%x", &value);
if (x != 1)
return -EINVAL;
pr_debug(KERN_ERR "%s, %d, 0x%x\n", ascii_value, x, value);
} else
return -EINVAL;
if (copy_from_user(&value, buf, sizeof(s32)))
return -EFAULT;
snprintf(name, PID_NAME_LEN, "process_%d", current->pid);
pm_qos_update_requirement(pm_qos_class, name, value);
return sizeof(s32);
pm_qos_req = (struct pm_qos_request_list *)filp->private_data;
pm_qos_update_request(pm_qos_req, value);
return count;
}

3
kernel/power/Makefile
View File

@ -8,7 +8,8 @@ obj-$(CONFIG_PM_SLEEP) += console.o
obj-$(CONFIG_FREEZER) += process.o
obj-$(CONFIG_SUSPEND) += suspend.o
obj-$(CONFIG_PM_TEST_SUSPEND) += suspend_test.o
obj-$(CONFIG_HIBERNATION) += hibernate.o snapshot.o swap.o user.o
obj-$(CONFIG_HIBERNATION) += hibernate.o snapshot.o swap.o user.o \
block_io.o
obj-$(CONFIG_HIBERNATION_NVS) += hibernate_nvs.o
obj-$(CONFIG_MAGIC_SYSRQ) += poweroff.o

103
kernel/power/block_io.c Normal file
View File

@ -0,0 +1,103 @@
/*
* This file provides functions for block I/O operations on swap/file.
*
* Copyright (C) 1998,2001-2005 Pavel Machek <pavel@ucw.cz>
* Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
*
* This file is released under the GPLv2.
*/
#include <linux/bio.h>
#include <linux/kernel.h>
#include <linux/pagemap.h>
#include <linux/swap.h>
#include "power.h"
/**
* submit - submit BIO request.
* @rw: READ or WRITE.
* @off physical offset of page.
* @page: page we're reading or writing.
* @bio_chain: list of pending biod (for async reading)
*
* Straight from the textbook - allocate and initialize the bio.
* If we're reading, make sure the page is marked as dirty.
* Then submit it and, if @bio_chain == NULL, wait.
*/
static int submit(int rw, struct block_device *bdev, sector_t sector,
struct page *page, struct bio **bio_chain)
{
const int bio_rw = rw | (1 << BIO_RW_SYNCIO) | (1 << BIO_RW_UNPLUG);
struct bio *bio;
bio = bio_alloc(__GFP_WAIT | __GFP_HIGH, 1);
bio->bi_sector = sector;
bio->bi_bdev = bdev;
bio->bi_end_io = end_swap_bio_read;
if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
printk(KERN_ERR "PM: Adding page to bio failed at %llu\n",
(unsigned long long)sector);
bio_put(bio);
return -EFAULT;
}
lock_page(page);
bio_get(bio);
if (bio_chain == NULL) {
submit_bio(bio_rw, bio);
wait_on_page_locked(page);
if (rw == READ)
bio_set_pages_dirty(bio);
bio_put(bio);
} else {
if (rw == READ)
get_page(page); /* These pages are freed later */
bio->bi_private = *bio_chain;
*bio_chain = bio;
submit_bio(bio_rw, bio);
}
return 0;
}
int hib_bio_read_page(pgoff_t page_off, void *addr, struct bio **bio_chain)
{
return submit(READ, hib_resume_bdev, page_off * (PAGE_SIZE >> 9),
virt_to_page(addr), bio_chain);
}
int hib_bio_write_page(pgoff_t page_off, void *addr, struct bio **bio_chain)
{
return submit(WRITE, hib_resume_bdev, page_off * (PAGE_SIZE >> 9),
virt_to_page(addr), bio_chain);
}
int hib_wait_on_bio_chain(struct bio **bio_chain)
{
struct bio *bio;
struct bio *next_bio;
int ret = 0;
if (bio_chain == NULL)
return 0;
bio = *bio_chain;
if (bio == NULL)
return 0;
while (bio) {
struct page *page;
next_bio = bio->bi_private;
page = bio->bi_io_vec[0].bv_page;
wait_on_page_locked(page);
if (!PageUptodate(page) || PageError(page))
ret = -EIO;
put_page(page);
bio_put(bio);
bio = next_bio;
}
*bio_chain = NULL;
return ret;
}

27
kernel/power/power.h
View File

@ -97,24 +97,12 @@ extern int hibernate_preallocate_memory(void);
*/
struct snapshot_handle {
loff_t offset; /* number of the last byte ready for reading
* or writing in the sequence
*/
unsigned int cur; /* number of the block of PAGE_SIZE bytes the
* next operation will refer to (ie. current)
*/
unsigned int cur_offset; /* offset with respect to the current
* block (for the next operation)
*/
unsigned int prev; /* number of the block of PAGE_SIZE bytes that
* was the current one previously
*/
void *buffer; /* address of the block to read from
* or write to
*/
unsigned int buf_offset; /* location to read from or write to,
* given as a displacement from 'buffer'
*/
int sync_read; /* Set to one to notify the caller of
* snapshot_write_next() that it may
* need to call wait_on_bio_chain()
@ -125,12 +113,12 @@ struct snapshot_handle {
* snapshot_read_next()/snapshot_write_next() is allowed to
* read/write data after the function returns
*/
#define data_of(handle) ((handle).buffer + (handle).buf_offset)
#define data_of(handle) ((handle).buffer)
extern unsigned int snapshot_additional_pages(struct zone *zone);
extern unsigned long snapshot_get_image_size(void);
extern int snapshot_read_next(struct snapshot_handle *handle, size_t count);
extern int snapshot_write_next(struct snapshot_handle *handle, size_t count);
extern int snapshot_read_next(struct snapshot_handle *handle);
extern int snapshot_write_next(struct snapshot_handle *handle);
extern void snapshot_write_finalize(struct snapshot_handle *handle);
extern int snapshot_image_loaded(struct snapshot_handle *handle);
@ -154,6 +142,15 @@ extern int swsusp_read(unsigned int *flags_p);
extern int swsusp_write(unsigned int flags);
extern void swsusp_close(fmode_t);
/* kernel/power/block_io.c */
extern struct block_device *hib_resume_bdev;
extern int hib_bio_read_page(pgoff_t page_off, void *addr,
struct bio **bio_chain);
extern int hib_bio_write_page(pgoff_t page_off, void *addr,
struct bio **bio_chain);
extern int hib_wait_on_bio_chain(struct bio **bio_chain);
struct timeval;
/* kernel/power/swsusp.c */
extern void swsusp_show_speed(struct timeval *, struct timeval *,

153
kernel/power/snapshot.c
View File

@ -1604,14 +1604,9 @@ pack_pfns(unsigned long *buf, struct memory_bitmap *bm)
* snapshot_handle structure. The structure gets updated and a pointer
* to it should be passed to this function every next time.
*
* The @count parameter should contain the number of bytes the caller
* wants to read from the snapshot. It must not be zero.
*
* On success the function returns a positive number. Then, the caller
* is allowed to read up to the returned number of bytes from the memory
* location computed by the data_of() macro. The number returned
* may be smaller than @count, but this only happens if the read would
* cross a page boundary otherwise.
* location computed by the data_of() macro.
*
* The function returns 0 to indicate the end of data stream condition,
* and a negative number is returned on error. In such cases the
@ -1619,7 +1614,7 @@ pack_pfns(unsigned long *buf, struct memory_bitmap *bm)
* any more.
*/
int snapshot_read_next(struct snapshot_handle *handle, size_t count)
int snapshot_read_next(struct snapshot_handle *handle)
{
if (handle->cur > nr_meta_pages + nr_copy_pages)
return 0;
@ -1630,7 +1625,7 @@ int snapshot_read_next(struct snapshot_handle *handle, size_t count)
if (!buffer)
return -ENOMEM;
}
if (!handle->offset) {
if (!handle->cur) {
int error;
error = init_header((struct swsusp_info *)buffer);
@ -1639,42 +1634,30 @@ int snapshot_read_next(struct snapshot_handle *handle, size_t count)
handle->buffer = buffer;
memory_bm_position_reset(&orig_bm);
memory_bm_position_reset(&copy_bm);
}
if (handle->prev < handle->cur) {
if (handle->cur <= nr_meta_pages) {
memset(buffer, 0, PAGE_SIZE);
pack_pfns(buffer, &orig_bm);
} else {
struct page *page;
page = pfn_to_page(memory_bm_next_pfn(&copy_bm));
if (PageHighMem(page)) {
/* Highmem pages are copied to the buffer,
* because we can't return with a kmapped
* highmem page (we may not be called again).
*/
void *kaddr;
kaddr = kmap_atomic(page, KM_USER0);
memcpy(buffer, kaddr, PAGE_SIZE);
kunmap_atomic(kaddr, KM_USER0);
handle->buffer = buffer;
} else {
handle->buffer = page_address(page);
}
}
handle->prev = handle->cur;
}
handle->buf_offset = handle->cur_offset;
if (handle->cur_offset + count >= PAGE_SIZE) {
count = PAGE_SIZE - handle->cur_offset;
handle->cur_offset = 0;
handle->cur++;
} else if (handle->cur <= nr_meta_pages) {
memset(buffer, 0, PAGE_SIZE);
pack_pfns(buffer, &orig_bm);
} else {
handle->cur_offset += count;
struct page *page;
page = pfn_to_page(memory_bm_next_pfn(&copy_bm));
if (PageHighMem(page)) {
/* Highmem pages are copied to the buffer,
* because we can't return with a kmapped
* highmem page (we may not be called again).
*/
void *kaddr;
kaddr = kmap_atomic(page, KM_USER0);
memcpy(buffer, kaddr, PAGE_SIZE);
kunmap_atomic(kaddr, KM_USER0);
handle->buffer = buffer;
} else {
handle->buffer = page_address(page);
}
}
handle->offset += count;
return count;
handle->cur++;
return PAGE_SIZE;
}
/**
@ -2133,14 +2116,9 @@ static void *get_buffer(struct memory_bitmap *bm, struct chain_allocator *ca)
* snapshot_handle structure. The structure gets updated and a pointer
* to it should be passed to this function every next time.
*
* The @count parameter should contain the number of bytes the caller
* wants to write to the image. It must not be zero.
*
* On success the function returns a positive number. Then, the caller
* is allowed to write up to the returned number of bytes to the memory
* location computed by the data_of() macro. The number returned
* may be smaller than @count, but this only happens if the write would
* cross a page boundary otherwise.
* location computed by the data_of() macro.
*
* The function returns 0 to indicate the "end of file" condition,
* and a negative number is returned on error. In such cases the
@ -2148,16 +2126,18 @@ static void *get_buffer(struct memory_bitmap *bm, struct chain_allocator *ca)
* any more.
*/
int snapshot_write_next(struct snapshot_handle *handle, size_t count)
int snapshot_write_next(struct snapshot_handle *handle)
{
static struct chain_allocator ca;
int error = 0;
/* Check if we have already loaded the entire image */
if (handle->prev && handle->cur > nr_meta_pages + nr_copy_pages)
if (handle->cur > 1 && handle->cur > nr_meta_pages + nr_copy_pages)
return 0;
if (handle->offset == 0) {
handle->sync_read = 1;
if (!handle->cur) {
if (!buffer)
/* This makes the buffer be freed by swsusp_free() */
buffer = get_image_page(GFP_ATOMIC, PG_ANY);
@ -2166,56 +2146,43 @@ int snapshot_write_next(struct snapshot_handle *handle, size_t count)
return -ENOMEM;
handle->buffer = buffer;
}
handle->sync_read = 1;
if (handle->prev < handle->cur) {
if (handle->prev == 0) {
error = load_header(buffer);
} else if (handle->cur == 1) {
error = load_header(buffer);
if (error)
return error;
error = memory_bm_create(&copy_bm, GFP_ATOMIC, PG_ANY);
if (error)
return error;
} else if (handle->cur <= nr_meta_pages + 1) {
error = unpack_orig_pfns(buffer, &copy_bm);
if (error)
return error;
if (handle->cur == nr_meta_pages + 1) {
error = prepare_image(&orig_bm, &copy_bm);
if (error)
return error;
error = memory_bm_create(&copy_bm, GFP_ATOMIC, PG_ANY);
if (error)
return error;
} else if (handle->prev <= nr_meta_pages) {
error = unpack_orig_pfns(buffer, &copy_bm);
if (error)
return error;
if (handle->prev == nr_meta_pages) {
error = prepare_image(&orig_bm, &copy_bm);
if (error)
return error;
chain_init(&ca, GFP_ATOMIC, PG_SAFE);
memory_bm_position_reset(&orig_bm);
restore_pblist = NULL;
handle->buffer = get_buffer(&orig_bm, &ca);
handle->sync_read = 0;
if (IS_ERR(handle->buffer))
return PTR_ERR(handle->buffer);
}
} else {
copy_last_highmem_page();
chain_init(&ca, GFP_ATOMIC, PG_SAFE);
memory_bm_position_reset(&orig_bm);
restore_pblist = NULL;
handle->buffer = get_buffer(&orig_bm, &ca);
handle->sync_read = 0;
if (IS_ERR(handle->buffer))
return PTR_ERR(handle->buffer);
if (handle->buffer != buffer)
handle->sync_read = 0;
}
handle->prev = handle->cur;
}
handle->buf_offset = handle->cur_offset;
if (handle->cur_offset + count >= PAGE_SIZE) {
count = PAGE_SIZE - handle->cur_offset;
handle->cur_offset = 0;
handle->cur++;
} else {
handle->cur_offset += count;
copy_last_highmem_page();
handle->buffer = get_buffer(&orig_bm, &ca);
if (IS_ERR(handle->buffer))
return PTR_ERR(handle->buffer);
if (handle->buffer != buffer)
handle->sync_read = 0;
}
handle->offset += count;
return count;
handle->cur++;
return PAGE_SIZE;
}
/**
@ -2230,7 +2197,7 @@ void snapshot_write_finalize(struct snapshot_handle *handle)
{
copy_last_highmem_page();
/* Free only if we have loaded the image entirely */
if (handle->prev && handle->cur > nr_meta_pages + nr_copy_pages) {
if (handle->cur > 1 && handle->cur > nr_meta_pages + nr_copy_pages) {
memory_bm_free(&orig_bm, PG_UNSAFE_CLEAR);
free_highmem_data();
}

333
kernel/power/swap.c
View File

@ -29,6 +29,40 @@
#define SWSUSP_SIG "S1SUSPEND"
/*
* The swap map is a data structure used for keeping track of each page
* written to a swap partition. It consists of many swap_map_page
* structures that contain each an array of MAP_PAGE_SIZE swap entries.
* These structures are stored on the swap and linked together with the
* help of the .next_swap member.
*
* The swap map is created during suspend. The swap map pages are
* allocated and populated one at a time, so we only need one memory
* page to set up the entire structure.
*
* During resume we also only need to use one swap_map_page structure
* at a time.
*/
#define MAP_PAGE_ENTRIES (PAGE_SIZE / sizeof(sector_t) - 1)
struct swap_map_page {
sector_t entries[MAP_PAGE_ENTRIES];
sector_t next_swap;
};
/**
* The swap_map_handle structure is used for handling swap in
* a file-alike way
*/
struct swap_map_handle {
struct swap_map_page *cur;
sector_t cur_swap;
sector_t first_sector;
unsigned int k;
};
struct swsusp_header {
char reserved[PAGE_SIZE - 20 - sizeof(sector_t) - sizeof(int)];
sector_t image;
@ -145,110 +179,24 @@ int swsusp_swap_in_use(void)
*/
static unsigned short root_swap = 0xffff;
static struct block_device *resume_bdev;
/**
* submit - submit BIO request.
* @rw: READ or WRITE.
* @off physical offset of page.
* @page: page we're reading or writing.
* @bio_chain: list of pending biod (for async reading)
*
* Straight from the textbook - allocate and initialize the bio.
* If we're reading, make sure the page is marked as dirty.
* Then submit it and, if @bio_chain == NULL, wait.
*/
static int submit(int rw, pgoff_t page_off, struct page *page,
struct bio **bio_chain)
{
const int bio_rw = rw | (1 << BIO_RW_SYNCIO) | (1 << BIO_RW_UNPLUG);
struct bio *bio;
bio = bio_alloc(__GFP_WAIT | __GFP_HIGH, 1);
bio->bi_sector = page_off * (PAGE_SIZE >> 9);
bio->bi_bdev = resume_bdev;
bio->bi_end_io = end_swap_bio_read;
if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
printk(KERN_ERR "PM: Adding page to bio failed at %ld\n",
page_off);
bio_put(bio);
return -EFAULT;
}
lock_page(page);
bio_get(bio);
if (bio_chain == NULL) {
submit_bio(bio_rw, bio);
wait_on_page_locked(page);
if (rw == READ)
bio_set_pages_dirty(bio);
bio_put(bio);
} else {
if (rw == READ)
get_page(page); /* These pages are freed later */
bio->bi_private = *bio_chain;
*bio_chain = bio;
submit_bio(bio_rw, bio);
}
return 0;
}
static int bio_read_page(pgoff_t page_off, void *addr, struct bio **bio_chain)
{
return submit(READ, page_off, virt_to_page(addr), bio_chain);
}
static int bio_write_page(pgoff_t page_off, void *addr, struct bio **bio_chain)
{
return submit(WRITE, page_off, virt_to_page(addr), bio_chain);
}
static int wait_on_bio_chain(struct bio **bio_chain)
{
struct bio *bio;
struct bio *next_bio;
int ret = 0;
if (bio_chain == NULL)
return 0;
bio = *bio_chain;
if (bio == NULL)
return 0;
while (bio) {
struct page *page;
next_bio = bio->bi_private;
page = bio->bi_io_vec[0].bv_page;
wait_on_page_locked(page);
if (!PageUptodate(page) || PageError(page))
ret = -EIO;
put_page(page);
bio_put(bio);
bio = next_bio;
}
*bio_chain = NULL;
return ret;
}
struct block_device *hib_resume_bdev;
/*
* Saving part
*/
static int mark_swapfiles(sector_t start, unsigned int flags)
static int mark_swapfiles(struct swap_map_handle *handle, unsigned int flags)
{
int error;
bio_read_page(swsusp_resume_block, swsusp_header, NULL);
hib_bio_read_page(swsusp_resume_block, swsusp_header, NULL);
if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) ||
!memcmp("SWAPSPACE2",swsusp_header->sig, 10)) {
memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10);
memcpy(swsusp_header->sig,SWSUSP_SIG, 10);
swsusp_header->image = start;
swsusp_header->image = handle->first_sector;
swsusp_header->flags = flags;
error = bio_write_page(swsusp_resume_block,
error = hib_bio_write_page(swsusp_resume_block,
swsusp_header, NULL);
} else {
printk(KERN_ERR "PM: Swap header not found!\n");
@ -260,25 +208,26 @@ static int mark_swapfiles(sector_t start, unsigned int flags)
/**
* swsusp_swap_check - check if the resume device is a swap device
* and get its index (if so)
*
* This is called before saving image
*/
static int swsusp_swap_check(void) /* This is called before saving image */
static int swsusp_swap_check(void)
{
int res;
res = swap_type_of(swsusp_resume_device, swsusp_resume_block,
&resume_bdev);
&hib_resume_bdev);
if (res < 0)
return res;
root_swap = res;
res = blkdev_get(resume_bdev, FMODE_WRITE);
res = blkdev_get(hib_resume_bdev, FMODE_WRITE);
if (res)
return res;
res = set_blocksize(resume_bdev, PAGE_SIZE);
res = set_blocksize(hib_resume_bdev, PAGE_SIZE);
if (res < 0)
blkdev_put(resume_bdev, FMODE_WRITE);
blkdev_put(hib_resume_bdev, FMODE_WRITE);
return res;
}
@ -309,42 +258,9 @@ static int write_page(void *buf, sector_t offset, struct bio **bio_chain)
} else {
src = buf;
}
return bio_write_page(offset, src, bio_chain);
return hib_bio_write_page(offset, src, bio_chain);
}
/*
* The swap map is a data structure used for keeping track of each page
* written to a swap partition. It consists of many swap_map_page
* structures that contain each an array of MAP_PAGE_SIZE swap entries.
* These structures are stored on the swap and linked together with the
* help of the .next_swap member.
*
* The swap map is created during suspend. The swap map pages are
* allocated and populated one at a time, so we only need one memory
* page to set up the entire structure.
*
* During resume we also only need to use one swap_map_page structure
* at a time.
*/
#define MAP_PAGE_ENTRIES (PAGE_SIZE / sizeof(sector_t) - 1)
struct swap_map_page {
sector_t entries[MAP_PAGE_ENTRIES];
sector_t next_swap;
};
/**
* The swap_map_handle structure is used for handling swap in
* a file-alike way
*/
struct swap_map_handle {
struct swap_map_page *cur;
sector_t cur_swap;
unsigned int k;
};
static void release_swap_writer(struct swap_map_handle *handle)
{
if (handle->cur)
@ -354,16 +270,33 @@ static void release_swap_writer(struct swap_map_handle *handle)
static int get_swap_writer(struct swap_map_handle *handle)
{
int ret;
ret = swsusp_swap_check();
if (ret) {
if (ret != -ENOSPC)
printk(KERN_ERR "PM: Cannot find swap device, try "
"swapon -a.\n");
return ret;
}
handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
if (!handle->cur)
return -ENOMEM;
if (!handle->cur) {
ret = -ENOMEM;
goto err_close;
}
handle->cur_swap = alloc_swapdev_block(root_swap);
if (!handle->cur_swap) {
release_swap_writer(handle);
return -ENOSPC;
ret = -ENOSPC;
goto err_rel;
}
handle->k = 0;
handle->first_sector = handle->cur_swap;
return 0;
err_rel:
release_swap_writer(handle);
err_close:
swsusp_close(FMODE_WRITE);
return ret;
}
static int swap_write_page(struct swap_map_handle *handle, void *buf,
@ -380,7 +313,7 @@ static int swap_write_page(struct swap_map_handle *handle, void *buf,
return error;
handle->cur->entries[handle->k++] = offset;
if (handle->k >= MAP_PAGE_ENTRIES) {
error = wait_on_bio_chain(bio_chain);
error = hib_wait_on_bio_chain(bio_chain);
if (error)
goto out;
offset = alloc_swapdev_block(root_swap);
@ -406,6 +339,24 @@ static int flush_swap_writer(struct swap_map_handle *handle)
return -EINVAL;
}
static int swap_writer_finish(struct swap_map_handle *handle,
unsigned int flags, int error)
{
if (!error) {
flush_swap_writer(handle);
printk(KERN_INFO "PM: S");
error = mark_swapfiles(handle, flags);
printk("|\n");
}
if (error)
free_all_swap_pages(root_swap);
release_swap_writer(handle);
swsusp_close(FMODE_WRITE);
return error;
}
/**
* save_image - save the suspend image data
*/
@ -431,7 +382,7 @@ static int save_image(struct swap_map_handle *handle,
bio = NULL;
do_gettimeofday(&start);
while (1) {
ret = snapshot_read_next(snapshot, PAGE_SIZE);
ret = snapshot_read_next(snapshot);
if (ret <= 0)
break;
ret = swap_write_page(handle, data_of(*snapshot), &bio);
@ -441,7 +392,7 @@ static int save_image(struct swap_map_handle *handle,
printk(KERN_CONT "\b\b\b\b%3d%%", nr_pages / m);
nr_pages++;
}
err2 = wait_on_bio_chain(&bio);
err2 = hib_wait_on_bio_chain(&bio);
do_gettimeofday(&stop);
if (!ret)
ret = err2;
@ -483,50 +434,34 @@ int swsusp_write(unsigned int flags)
struct swap_map_handle handle;
struct snapshot_handle snapshot;
struct swsusp_info *header;
unsigned long pages;
int error;
error = swsusp_swap_check();
pages = snapshot_get_image_size();
error = get_swap_writer(&handle);
if (error) {
printk(KERN_ERR "PM: Cannot find swap device, try "
"swapon -a.\n");
printk(KERN_ERR "PM: Cannot get swap writer\n");
return error;
}
if (!enough_swap(pages)) {
printk(KERN_ERR "PM: Not enough free swap\n");
error = -ENOSPC;
goto out_finish;
}
memset(&snapshot, 0, sizeof(struct snapshot_handle));
error = snapshot_read_next(&snapshot, PAGE_SIZE);
error = snapshot_read_next(&snapshot);
if (error < PAGE_SIZE) {
if (error >= 0)
error = -EFAULT;
goto out;
goto out_finish;
}
header = (struct swsusp_info *)data_of(snapshot);
if (!enough_swap(header->pages)) {
printk(KERN_ERR "PM: Not enough free swap\n");
error = -ENOSPC;
goto out;
}
error = get_swap_writer(&handle);
if (!error) {
sector_t start = handle.cur_swap;
error = swap_write_page(&handle, header, NULL);
if (!error)
error = save_image(&handle, &snapshot,
header->pages - 1);
if (!error) {
flush_swap_writer(&handle);
printk(KERN_INFO "PM: S");
error = mark_swapfiles(start, flags);
printk("|\n");
}
}
if (error)
free_all_swap_pages(root_swap);
release_swap_writer(&handle);
out:
swsusp_close(FMODE_WRITE);
error = swap_write_page(&handle, header, NULL);
if (!error)
error = save_image(&handle, &snapshot, pages - 1);
out_finish:
error = swap_writer_finish(&handle, flags, error);
return error;
}
@ -542,18 +477,21 @@ static void release_swap_reader(struct swap_map_handle *handle)
handle->cur = NULL;
}
static int get_swap_reader(struct swap_map_handle *handle, sector_t start)
static int get_swap_reader(struct swap_map_handle *handle,
unsigned int *flags_p)
{
int error;
if (!start)
*flags_p = swsusp_header->flags;
if (!swsusp_header->image) /* how can this happen? */
return -EINVAL;
handle->cur = (struct swap_map_page *)get_zeroed_page(__GFP_WAIT | __GFP_HIGH);
if (!handle->cur)
return -ENOMEM;
error = bio_read_page(start, handle->cur, NULL);
error = hib_bio_read_page(swsusp_header->image, handle->cur, NULL);
if (error) {
release_swap_reader(handle);
return error;
@ -573,21 +511,28 @@ static int swap_read_page(struct swap_map_handle *handle, void *buf,
offset = handle->cur->entries[handle->k];
if (!offset)
return -EFAULT;
error = bio_read_page(offset, buf, bio_chain);
error = hib_bio_read_page(offset, buf, bio_chain);
if (error)
return error;
if (++handle->k >= MAP_PAGE_ENTRIES) {
error = wait_on_bio_chain(bio_chain);
error = hib_wait_on_bio_chain(bio_chain);
handle->k = 0;
offset = handle->cur->next_swap;
if (!offset)
release_swap_reader(handle);
else if (!error)
error = bio_read_page(offset, handle->cur, NULL);
error = hib_bio_read_page(offset, handle->cur, NULL);
}
return error;
}
static int swap_reader_finish(struct swap_map_handle *handle)
{
release_swap_reader(handle);
return 0;
}
/**
* load_image - load the image using the swap map handle
* @handle and the snapshot handle @snapshot
@ -615,21 +560,21 @@ static int load_image(struct swap_map_handle *handle,
bio = NULL;
do_gettimeofday(&start);
for ( ; ; ) {
error = snapshot_write_next(snapshot, PAGE_SIZE);
error = snapshot_write_next(snapshot);
if (error <= 0)
break;
error = swap_read_page(handle, data_of(*snapshot), &bio);
if (error)
break;
if (snapshot->sync_read)
error = wait_on_bio_chain(&bio);
error = hib_wait_on_bio_chain(&bio);
if (error)
break;
if (!(nr_pages % m))
printk("\b\b\b\b%3d%%", nr_pages / m);
nr_pages++;
}
err2 = wait_on_bio_chain(&bio);
err2 = hib_wait_on_bio_chain(&bio);
do_gettimeofday(&stop);
if (!error)
error = err2;
@ -657,20 +602,20 @@ int swsusp_read(unsigned int *flags_p)
struct snapshot_handle snapshot;
struct swsusp_info *header;
*flags_p = swsusp_header->flags;
memset(&snapshot, 0, sizeof(struct snapshot_handle));
error = snapshot_write_next(&snapshot, PAGE_SIZE);
error = snapshot_write_next(&snapshot);
if (error < PAGE_SIZE)
return error < 0 ? error : -EFAULT;
header = (struct swsusp_info *)data_of(snapshot);
error = get_swap_reader(&handle, swsusp_header->image);
error = get_swap_reader(&handle, flags_p);
if (error)
goto end;
if (!error)
error = swap_read_page(&handle, header, NULL);
if (!error)
error = load_image(&handle, &snapshot, header->pages - 1);
release_swap_reader(&handle);
swap_reader_finish(&handle);
end:
if (!error)
pr_debug("PM: Image successfully loaded\n");
else
@ -686,11 +631,11 @@ int swsusp_check(void)
{
int error;
resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ);
if (!IS_ERR(resume_bdev)) {
set_blocksize(resume_bdev, PAGE_SIZE);
hib_resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ);
if (!IS_ERR(hib_resume_bdev)) {
set_blocksize(hib_resume_bdev, PAGE_SIZE);
memset(swsusp_header, 0, PAGE_SIZE);
error = bio_read_page(swsusp_resume_block,
error = hib_bio_read_page(swsusp_resume_block,
swsusp_header, NULL);
if (error)
goto put;
@ -698,7 +643,7 @@ int swsusp_check(void)
if (!memcmp(SWSUSP_SIG, swsusp_header->sig, 10)) {
memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
/* Reset swap signature now */
error = bio_write_page(swsusp_resume_block,
error = hib_bio_write_page(swsusp_resume_block,
swsusp_header, NULL);
} else {
error = -EINVAL;
@ -706,11 +651,11 @@ int swsusp_check(void)
put:
if (error)
blkdev_put(resume_bdev, FMODE_READ);
blkdev_put(hib_resume_bdev, FMODE_READ);
else
pr_debug("PM: Signature found, resuming\n");
} else {
error = PTR_ERR(resume_bdev);
error = PTR_ERR(hib_resume_bdev);
}
if (error)
@ -725,12 +670,12 @@ put:
void swsusp_close(fmode_t mode)
{
if (IS_ERR(resume_bdev)) {
if (IS_ERR(hib_resume_bdev)) {
pr_debug("PM: Image device not initialised\n");
return;
}
blkdev_put(resume_bdev, mode);
blkdev_put(hib_resume_bdev, mode);
}
static int swsusp_header_init(void)

37
kernel/power/user.c
View File

@ -151,6 +151,7 @@ static ssize_t snapshot_read(struct file *filp, char __user *buf,
{
struct snapshot_data *data;
ssize_t res;
loff_t pg_offp = *offp & ~PAGE_MASK;
mutex_lock(&pm_mutex);
@ -159,14 +160,19 @@ static ssize_t snapshot_read(struct file *filp, char __user *buf,
res = -ENODATA;
goto Unlock;
}
res = snapshot_read_next(&data->handle, count);
if (res > 0) {
if (copy_to_user(buf, data_of(data->handle), res))
res = -EFAULT;
else
*offp = data->handle.offset;
if (!pg_offp) { /* on page boundary? */
res = snapshot_read_next(&data->handle);
if (res <= 0)
goto Unlock;
} else {
res = PAGE_SIZE - pg_offp;
}
res = simple_read_from_buffer(buf, count, &pg_offp,
data_of(data->handle), res);
if (res > 0)
*offp += res;
Unlock:
mutex_unlock(&pm_mutex);
@ -178,18 +184,25 @@ static ssize_t snapshot_write(struct file *filp, const char __user *buf,
{
struct snapshot_data *data;
ssize_t res;
loff_t pg_offp = *offp & ~PAGE_MASK;
mutex_lock(&pm_mutex);
data = filp->private_data;
res = snapshot_write_next(&data->handle, count);
if (res > 0) {
if (copy_from_user(data_of(data->handle), buf, res))
res = -EFAULT;
else
*offp = data->handle.offset;
if (!pg_offp) {
res = snapshot_write_next(&data->handle);
if (res <= 0)
goto unlock;
} else {
res = PAGE_SIZE - pg_offp;
}
res = simple_write_to_buffer(data_of(data->handle), res, &pg_offp,
buf, count);
if (res > 0)
*offp += res;
unlock:
mutex_unlock(&pm_mutex);
return res;

2
net/mac80211/mlme.c
View File

@ -495,7 +495,7 @@ void ieee80211_recalc_ps(struct ieee80211_local *local, s32 latency)
s32 beaconint_us;
if (latency < 0)
latency = pm_qos_requirement(PM_QOS_NETWORK_LATENCY);
latency = pm_qos_request(PM_QOS_NETWORK_LATENCY);
beaconint_us = ieee80211_tu_to_usec(
found->vif.bss_conf.beacon_int);

3
sound/core/pcm.c
View File

@ -648,9 +648,6 @@ int snd_pcm_new_stream(struct snd_pcm *pcm, int stream, int substream_count)
substream->number = idx;
substream->stream = stream;
sprintf(substream->name, "subdevice #%i", idx);
snprintf(substream->latency_id, sizeof(substream->latency_id),
"ALSA-PCM%d-%d%c%d", pcm->card->number, pcm->device,
(stream ? 'c' : 'p'), idx);
substream->buffer_bytes_max = UINT_MAX;
if (prev == NULL)
pstr->substream = substream;

14
sound/core/pcm_native.c
View File

@ -484,11 +484,13 @@ static int snd_pcm_hw_params(struct snd_pcm_substream *substream,
snd_pcm_timer_resolution_change(substream);
runtime->status->state = SNDRV_PCM_STATE_SETUP;
pm_qos_remove_requirement(PM_QOS_CPU_DMA_LATENCY,
substream->latency_id);
if (substream->latency_pm_qos_req) {
pm_qos_remove_request(substream->latency_pm_qos_req);
substream->latency_pm_qos_req = NULL;
}
if ((usecs = period_to_usecs(runtime)) >= 0)
pm_qos_add_requirement(PM_QOS_CPU_DMA_LATENCY,
substream->latency_id, usecs);
substream->latency_pm_qos_req = pm_qos_add_request(
PM_QOS_CPU_DMA_LATENCY, usecs);
return 0;
_error:
/* hardware might be unuseable from this time,
@ -543,8 +545,8 @@ static int snd_pcm_hw_free(struct snd_pcm_substream *substream)
if (substream->ops->hw_free)
result = substream->ops->hw_free(substream);
runtime->status->state = SNDRV_PCM_STATE_OPEN;
pm_qos_remove_requirement(PM_QOS_CPU_DMA_LATENCY,
substream->latency_id);
pm_qos_remove_request(substream->latency_pm_qos_req);
substream->latency_pm_qos_req = NULL;
return result;
}