Now that the driver core supports dev_groups for individual drivers,
expose that pointer to struct usb_device_driver to make it easier for USB
drivers to also use it.
Yes, users of usb_device_driver are much rare, but there are instances
already that use custom sysfs files, so adding this support will make
things easier for those drivers. usbip is one example, hubs might be
another one.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20190806144502.17792-3-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Now that the driver core supports dev_groups for individual drivers,
expose that pointer to struct usb_driver to make it easier for USB
drivers to also use it.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20190806144502.17792-2-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The syzkaller fuzzer reported a bug in the USB hub driver which turned
out to be caused by a negative runtime-PM usage counter. This allowed
a hub to be runtime suspended at a time when the driver did not expect
it. The symptom is a WARNING issued because the hub's status URB is
submitted while it is already active:
URB 0000000031fb463e submitted while active
WARNING: CPU: 0 PID: 2917 at drivers/usb/core/urb.c:363
The negative runtime-PM usage count was caused by an unfortunate
design decision made when runtime PM was first implemented for USB.
At that time, USB class drivers were allowed to unbind from their
interfaces without balancing the usage counter (i.e., leaving it with
a positive count). The core code would take care of setting the
counter back to 0 before allowing another driver to bind to the
interface.
Later on when runtime PM was implemented for the entire kernel, the
opposite decision was made: Drivers were required to balance their
runtime-PM get and put calls. In order to maintain backward
compatibility, however, the USB subsystem adapted to the new
implementation by keeping an independent usage counter for each
interface and using it to automatically adjust the normal usage
counter back to 0 whenever a driver was unbound.
This approach involves duplicating information, but what is worse, it
doesn't work properly in cases where a USB class driver delays
decrementing the usage counter until after the driver's disconnect()
routine has returned and the counter has been adjusted back to 0.
Doing so would cause the usage counter to become negative. There's
even a warning about this in the USB power management documentation!
As it happens, this is exactly what the hub driver does. The
kick_hub_wq() routine increments the runtime-PM usage counter, and the
corresponding decrement is carried out by hub_event() in the context
of the hub_wq work-queue thread. This work routine may sometimes run
after the driver has been unbound from its interface, and when it does
it causes the usage counter to go negative.
It is not possible for hub_disconnect() to wait for a pending
hub_event() call to finish, because hub_disconnect() is called with
the device lock held and hub_event() acquires that lock. The only
feasible fix is to reverse the original design decision: remove the
duplicate interface-specific usage counter and require USB drivers to
balance their runtime PM gets and puts. As far as I know, all
existing drivers currently do this.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-and-tested-by: syzbot+7634edaea4d0b341c625@syzkaller.appspotmail.com
CC: <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
USB Bluetooth controller QCA ROME (0cf3:e007) sometimes stops working
after S3:
[ 165.110742] Bluetooth: hci0: using NVM file: qca/nvm_usb_00000302.bin
[ 168.432065] Bluetooth: hci0: Failed to send body at 4 of 1953 (-110)
After some experiments, I found that disabling LPM can workaround the
issue.
On some platforms, the USB power is cut during S3, so the driver uses
reset-resume to resume the device. During port resume, LPM gets enabled
twice, by usb_reset_and_verify_device() and usb_port_resume().
Consolidate all checks into new LPM helpers to make sure LPM only gets
enabled once.
Fixes: de68bab4fa ("usb: Don't enable USB 2.0 Link PM by default.”)
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Cc: stable <stable@vger.kernel.org> # after much soaking
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Use new helpers to make LPM enabling/disabling more clear.
This is a preparation to subsequent patch.
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Cc: stable <stable@vger.kernel.org> # after much soaking
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fixes gcc '-Wunused-but-set-variable' warning:
drivers/usb/core/driver.c: In function 'usb_driver_claim_interface':
drivers/usb/core/driver.c:513:21: warning:
variable 'udev' set but not used [-Wunused-but-set-variable]
Since commit c183813fce ("USB: remove LPM management from
usb_driver_claim_interface()"), 'udev' is not used.
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The syzbot fuzzing project found a use-after-free bug in the USB
core. The bug was caused by usbfs not unbinding from an interface
when the USB device file was closed, which led another process to
attempt the unbind later on, after the private data structure had been
deallocated.
The reason usbfs did not unbind the interface at the appropriate time
was because it thought the interface had never been claimed in the
first place. This was caused by the fact that
usb_driver_claim_interface() does not clean up properly when
device_bind_driver() returns an error. Although the error code gets
passed back to the caller, the iface->dev.driver pointer remains set
and iface->condition remains equal to USB_INTERFACE_BOUND.
This patch adds proper error handling to usb_driver_claim_interface().
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: syzbot+f84aa7209ccec829536f@syzkaller.appspotmail.com
CC: <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
usb_driver_claim_interface() disables and re-enables Link Power
Management, but it shouldn't do either one, for the reasons listed
below. This patch removes the two LPM-related function calls from the
routine.
The reason for disabling LPM in the analogous function
usb_probe_interface() is so that drivers won't have to deal with
unwanted LPM transitions in their probe routine. But
usb_driver_claim_interface() doesn't call the driver's probe routine
(or any other callbacks), so that reason doesn't apply here.
Furthermore, no driver other than usbfs will ever call
usb_driver_claim_interface() unless it is already bound to another
interface in the same device, which means disabling LPM here would be
redundant. usbfs doesn't interact with LPM at all.
Lastly, the error return from usb_unlocked_disable_lpm() isn't handled
properly; the code doesn't clean up its earlier actions before
returning.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Fixes: 8306095fd2 ("USB: Disable USB 3.0 LPM in critical sections.")
CC: <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
SoC have internal I/O buses that can't be proved for devices. The
devices on the buses can be accessed directly without additinal
configuration required. This type of bus is represented as
"simple-bus". In some platforms, we name "soc" with "simple-bus"
attribute and many devices are hooked under it described in DT
(device tree).
In commit bf74ad5bc4 ("Hold the device's parent's lock during
probe and remove") to solve USB subsystem lock sequence since
USB device's characteristic. Thus "soc" needs to be locked
whenever a device and driver's probing happen under "soc" bus.
During this period, an async driver tries to probe a device which
is under the "soc" bus would be blocked until previous driver
finish the probing and release "soc" lock. And the next probing
under the "soc" bus need to wait for async finish. Because of
that, driver's async probe for init time improvement will be
shadowed.
Since many devices don't have USB devices' characteristic, they
actually don't need parent's lock. Thus, we introduce a lock flag
in bus_type struct and driver core would lock the parent lock base
on the flag. For USB, we set this flag in usb_bus_type to keep
original lock behavior in driver core.
Async probe could have more benefit after this patch.
Signed-off-by: Martin Liu <liumartin@google.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Interface drivers like btusb that don't support reset-resume will be
rebound at resume if port was reset. Rebind is done during the pm_ops
.complete callback when probe returns EPROBE_DEFER as default.
Remove the "rebind failed: -517" message.
Device probe will eventually take place later.
[one-liner by Jerry Snitselaar posted in a mailing list question -Mathias]
Suggested-by: Jerry Snitselaar <jsnitsel@redhat.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Using a period after a newline causes bad output.
Miscellanea:
o Coalesce formats too
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This new helper is a simple wrapper around usb_get_status(). This
patch is in preparation to adding support for fetching PTM_STATUS
types. No functional changes.
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To match the rest of the kernel, the SPDX tags for the drivers/usb/core/
files are moved to the first line of the file. This makes it more
obvious the tag is present as well as making it match the other 12k
files in the tree with this location.
It also uses // to match the "expected style" as well.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
While running a bind/unbind stress test with the dwc3 usb driver on rk3399,
the following crash was observed.
Unable to handle kernel NULL pointer dereference at virtual address 00000218
pgd = ffffffc00165f000
[00000218] *pgd=000000000174f003, *pud=000000000174f003,
*pmd=0000000001750003, *pte=00e8000001751713
Internal error: Oops: 96000005 [#1] PREEMPT SMP
Modules linked in: uinput uvcvideo videobuf2_vmalloc cmac
ipt_MASQUERADE nf_nat_masquerade_ipv4 iptable_nat nf_nat_ipv4 nf_nat rfcomm
xt_mark fuse bridge stp llc zram btusb btrtl btbcm btintel bluetooth
ip6table_filter mwifiex_pcie mwifiex cfg80211 cdc_ether usbnet r8152 mii joydev
snd_seq_midi snd_seq_midi_event snd_rawmidi snd_seq snd_seq_device ppp_async
ppp_generic slhc tun
CPU: 1 PID: 29814 Comm: kworker/1:1 Not tainted 4.4.52 #507
Hardware name: Google Kevin (DT)
Workqueue: pm pm_runtime_work
task: ffffffc0ac540000 ti: ffffffc0af4d4000 task.ti: ffffffc0af4d4000
PC is at autosuspend_check+0x74/0x174
LR is at autosuspend_check+0x70/0x174
...
Call trace:
[<ffffffc00080dcc0>] autosuspend_check+0x74/0x174
[<ffffffc000810500>] usb_runtime_idle+0x20/0x40
[<ffffffc000785ae0>] __rpm_callback+0x48/0x7c
[<ffffffc000786af0>] rpm_idle+0x1e8/0x498
[<ffffffc000787cdc>] pm_runtime_work+0x88/0xcc
[<ffffffc000249bb8>] process_one_work+0x390/0x6b8
[<ffffffc00024abcc>] worker_thread+0x480/0x610
[<ffffffc000251a80>] kthread+0x164/0x178
[<ffffffc0002045d0>] ret_from_fork+0x10/0x40
Source:
(gdb) l *0xffffffc00080dcc0
0xffffffc00080dcc0 is in autosuspend_check
(drivers/usb/core/driver.c:1778).
1773 /* We don't need to check interfaces that are
1774 * disabled for runtime PM. Either they are unbound
1775 * or else their drivers don't support autosuspend
1776 * and so they are permanently active.
1777 */
1778 if (intf->dev.power.disable_depth)
1779 continue;
1780 if (atomic_read(&intf->dev.power.usage_count) > 0)
1781 return -EBUSY;
1782 w |= intf->needs_remote_wakeup;
Code analysis shows that intf is set to NULL in usb_disable_device() prior
to setting actconfig to NULL. At the same time, usb_runtime_idle() does not
lock the usb device, and neither does any of the functions in the
traceback. This means that there is no protection against a race condition
where usb_disable_device() is removing dev->actconfig->interface[] pointers
while those are being accessed from autosuspend_check().
To solve the problem, synchronize and validate device state between
autosuspend_check() and usb_disconnect().
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Some of the USB core files were missing explicit license information.
As all files in the kernel tree are implicitly licensed under the
GPLv2-only, be explicit in case someone get confused looking at
individual files by using the SPDX nomenclature.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When a USB driver is bound to an interface (either through probing or
by claiming it) or is unbound from an interface, the USB core always
disables Link Power Management during the transition and then
re-enables it afterward. The reason is because the driver might want
to prevent hub-initiated link power transitions, in which case the HCD
would have to recalculate the various LPM parameters. This
recalculation takes place when LPM is re-enabled and the new
parameters are sent to the device and its parent hub.
However, if the driver does not want to prevent hub-initiated link
power transitions then none of this work is necessary. The parameters
don't need to be recalculated, and LPM doesn't need to be disabled and
re-enabled.
It turns out that disabling and enabling LPM can be time-consuming,
enough so that it interferes with user programs that want to claim and
release interfaces rapidly via usbfs. Since the usbfs kernel driver
doesn't set the disable_hub_initiated_lpm flag, we can speed things up
and get the user programs to work by leaving LPM alone whenever the
flag isn't set.
And while we're improving the way disable_hub_initiated_lpm gets used,
let's also fix its kerneldoc.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Matthew Giassa <matthew@giassa.net>
CC: Mathias Nyman <mathias.nyman@intel.com>
CC: <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Attacks that trick drivers into passing a NULL pointer
to usb_driver_claim_interface() using forged descriptors are
known. This thwarts them by sanity checking.
Signed-off-by: Oliver Neukum <ONeukum@suse.com>
CC: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Use kmalloc_array instead of kmalloc to allocate memory for an array.
Also, remove the dev_warn for a memory leak, making the if check more
sleek.
Signed-off-by: Muhammad Falak R Wani <falakreyaz@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Driver probings and interface claims get rejected
if an interface is not authorized.
Signed-off-by: Stefan Koch <stefan.koch10@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit de7718bd9c as the
signed-off-by address is invalid.
Cc: Stefan Koch <stefan.koch10@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Driver probings and interface claims get rejected
if an interface is not authorized.
Signed-off-by: Stefan Koch <skoch@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently the USB stack assumes that all host controller drivers are
capable of receiving wakeup requests from downstream devices.
However, this isn't true for the isp1760-hcd driver, which means that
it isn't safe to do a runtime suspend of any device attached to a
root-hub port if the device requires wakeup.
This patch adds a "cant_recv_wakeups" flag to the usb_hcd structure
and sets the flag in isp1760-hcd. The core is modified to prevent a
direct child of the root hub from being put into runtime suspend with
wakeup enabled if the flag is set.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Nicolas Pitre <nico@linaro.org>
CC: <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>
The USB stack provides a mechanism for drivers to request an
asynchronous device reset (usb_queue_reset_device()). The mechanism
uses a work item (reset_ws) embedded in the usb_interface structure
used by the driver, and the reset is carried out by a work queue
routine.
The asynchronous reset can race with driver unbinding. When this
happens, we try to cancel the queued reset before unbinding the
driver, on the theory that the driver won't care about any resets once
it is unbound.
However, thanks to the fact that lockdep now tracks work queue
accesses, this can provoke a lockdep warning in situations where the
device reset causes another interface's driver to be unbound; see
http://marc.info/?l=linux-usb&m=141893165203776&w=2
for an example. The reason is that the work routine for reset_ws in
one interface calls cancel_queued_work() for the reset_ws in another
interface. Lockdep thinks this might lead to a work routine trying to
cancel itself. The simplest solution is not to cancel queued resets
when unbinding drivers.
This means we now need to acquire a reference to the usb_interface
when queuing a reset_ws work item and to drop the reference when the
work routine finishes. We also need to make sure that the
usb_interface structure doesn't outlive its parent usb_device; this
means acquiring and dropping a reference when the interface is created
and destroyed.
In addition, cancelling a queued reset can fail (if the device is in
the middle of an earlier reset), and this can cause usb_reset_device()
to try to rebind an interface that has been deallocated (see
http://marc.info/?l=linux-usb&m=142175717016628&w=2 for details).
Acquiring the extra references prevents this failure.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: Russell King - ARM Linux <linux@arm.linux.org.uk>
Reported-by: Olivier Sobrie <olivier@sobrie.be>
Tested-by: Olivier Sobrie <olivier@sobrie.be>
Cc: stable <stable@vger.kernel.org> # 3.19
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
After commit b2b49ccbdd (PM: Kconfig: Set PM_RUNTIME if PM_SLEEP is
selected) PM_RUNTIME is always set if PM is set, so quite a few
depend on CONFIG_PM (or even dropped in some cases).
Replace CONFIG_PM_RUNTIME with CONFIG_PM in the USB core code
and documentation.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When a host controller dies, we don't need to wait for a driver to
time out. We can shut down its URBs immediately. Without this
change, we can end up waiting 30 seconds for a mass-storage transfer
to time out.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Not all host controller drivers have bus-suspend and bus-resume
methods. When one doesn't, it will cause problems if runtime PM is
enabled in the kernel. The PM core will attempt to suspend the
controller's root hub, the suspend will fail because there is no
bus-suspend routine, and a -EBUSY error code will be returned to the
PM core. This will cause the suspend attempt to be repeated shortly
thereafter, in a never-ending loop.
Part of the problem is that the original error code -ENOENT gets
changed to -EBUSY in usb_runtime_suspend(), on the grounds that the PM
core will interpret -ENOENT as meaning that the root hub has gotten
into a runtime-PM error state. While this change is appropriate for
real USB devices, it's not such a good idea for a root hub. In fact,
considering the root hub to be in a runtime-PM error state would not
be far from the truth. Therefore this patch updates
usb_runtime_suspend() so that it adjusts error codes only for
non-root-hub devices.
Furthermore, the patch attempts to prevent the problem from occurring
in the first place by not enabling runtime PM by default for root hubs
whose host controller driver doesn't have bus_suspend and bus_resume
methods.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: Will Deacon <will.deacon@arm.com>
Tested-by: Will Deacon <will.deacon@arm.com>
CC: <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When a driver doesn't have pre_reset, post_reset, or reset_resume
methods, the USB core unbinds that driver when its device undergoes a
reset or a reset-resume, and then rebinds it afterward.
The existing straightforward implementation can lead to problems,
because each interface gets unbound and rebound before the next
interface is handled. If a driver claims additional interfaces, the
claim may fail because the old binding instance may still own the
additional interface when the new instance tries to claim it.
This patch fixes the problem by first unbinding all the interfaces
that are marked (i.e., their needs_binding flag is set) and then
rebinding all of them.
The patch also makes the helper functions in driver.c a little more
uniform and adjusts some out-of-date comments.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-and-tested-by: "Poulain, Loic" <loic.poulain@intel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Documentation/usb/bulk-streams.txt says:
All stream IDs will be deallocated when the driver releases the interface, to
ensure that drivers that don't support streams will be able to use the endpoint
This commit actually implements this.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
This modifies the probing order so that any matching
dynamic entry always will be used, even if the driver
has a matching static entry.
It is sometimes useful to dynamically update existing
device entries. With the new ability to set the dynamic
entry driver_info field, this can be used to test new
additions to class driver exception lists or proposed
changes to existing static per-device driver_info
entries.
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fix a memory leak in the usb_store_new_id() error paths. When bailing out
due to sanity checks, the function left the already allocated usb_dynid
struct in place. This regression was introduced by the following commits:
c63fe8f6 (usb: core: add sanity checks when using bInterfaceClass with new_id)
1b9fb31f (usb: core: check for valid id_table when using the RefId feature)
52a6966c (usb: core: bail out if user gives an unknown RefId when using new_id)
Detected by Coverity: CID 1162604.
Signed-off-by: Christian Engelmayer <cengelma@gmx.at>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When implementing the RefId feature, it was missed that id_tables can be
NULL under special circumstances. Bail out in that case.
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If users use the new RefId feature of new_id, give them an error message
if they provided an unknown reference. That helps detecting typos.
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Often, usb drivers need some driver_info to get a device to work. To
have access to driver_info when using new_id, allow to pass a reference
vendor:product tuple from which new_id will inherit driver_info.
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Check if that field is actually used and if so, bail out if it exeeds a
u8. Make it also future-proof by not requiring "exactly three"
parameters in new_id, but simply "more than two".
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch changes a dev_warn() call in usbcore to dev_dbg(). It's
not necessary to warn about drivers missing a reset-resume callback,
since the reset-resume method is optional.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
How it's supposed to work:
--------------------------
USB 2.0 Link PM is a lower power state that some newer USB 2.0 devices
support. USB 3.0 devices certified by the USB-IF are required to
support it if they are plugged into a USB 2.0 only port, or a USB 2.0
cable is used. USB 2.0 Link PM requires both a USB device and a host
controller that supports USB 2.0 hardware-enabled LPM.
USB 2.0 Link PM is designed to be enabled once by software, and the host
hardware handles transitions to the L1 state automatically. The premise
of USB 2.0 Link PM is to be able to put the device into a lower power
link state when the bus is idle or the device NAKs USB IN transfers for
a specified amount of time.
...but hardware is broken:
--------------------------
It turns out many USB 3.0 devices claim to support USB 2.0 Link PM (by
setting the LPM bit in their USB 2.0 BOS descriptor), but they don't
actually implement it correctly. This manifests as the USB device
refusing to respond to transfers when it is plugged into a USB 2.0 only
port under the Haswell-ULT/Lynx Point LP xHCI host.
These devices pass the xHCI driver's simple test to enable USB 2.0 Link
PM, wait for the port to enter L1, and then bring it back into L0. They
only start to break when L1 entry is interleaved with transfers.
Some devices then fail to respond to the next control transfer (usually
a Set Configuration). This results in devices never enumerating.
Other mass storage devices (such as a later model Western Digital My
Passport USB 3.0 hard drive) respond fine to going into L1 between
control transfers. They ACK the entry, come out of L1 when the host
needs to send a control transfer, and respond properly to those control
transfers. However, when the first READ10 SCSI command is sent, the
device NAKs the data phase while it's reading from the spinning disk.
Eventually, the host requests to put the link into L1, and the device
ACKs that request. Then it never responds to the data phase of the
READ10 command. This results in not being able to read from the drive.
Some mass storage devices (like the Corsair Survivor USB 3.0 flash
drive) are well behaved. They ACK the entry into L1 during control
transfers, and when SCSI commands start coming in, they NAK the requests
to go into L1, because they need to be at full power.
Not all USB 3.0 devices advertise USB 2.0 link PM support. My Point
Grey USB 3.0 webcam advertises itself as a USB 2.1 device, but doesn't
have a USB 2.0 BOS descriptor, so we don't enable USB 2.0 Link PM. I
suspect that means the device isn't certified.
What do we do about it?
-----------------------
There's really no good way for the kernel to test these devices.
Therefore, the kernel needs to disable USB 2.0 Link PM by default, and
distros will have to enable it by writing 1 to the sysfs file
/sys/bus/usb/devices/../power/usb2_hardware_lpm. Rip out the xHCI Link
PM test, since it's not sufficient to detect these buggy devices, and
don't automatically enable LPM after the device is addressed.
This patch should be backported to kernels as old as 3.11, that
contain the commit a558ccdcc7 "usb: xhci:
add USB2 Link power management BESL support". Without this fix, some
USB 3.0 devices will not enumerate or work properly under USB 2.0 ports
on Haswell-ULT systems.
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable@vger.kernel.org
When building the htmldocs (in verbose mode), scripts/kernel-doc reports the
following type of warnings:
Warning(drivers/usb/core/usb.c:76): No description found for return value of
'usb_find_alt_setting'
Fix them by:
- adding some missing descriptions of return values
- using "Return" sections for those descriptions
Signed-off-by: Yacine Belkadi <yacine.belkadi.1@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The "runtime idle" helper routine, rpm_idle(), currently ignores
return values from .runtime_idle() callbacks executed by it.
However, it turns out that many subsystems use
pm_generic_runtime_idle() which checks the return value of the
driver's callback and executes pm_runtime_suspend() for the device
unless that value is not 0. If that logic is moved to rpm_idle()
instead, pm_generic_runtime_idle() can be dropped and its users
will not need any .runtime_idle() callbacks any more.
Moreover, the PCI, SCSI, and SATA subsystems' .runtime_idle()
routines, pci_pm_runtime_idle(), scsi_runtime_idle(), and
ata_port_runtime_idle(), respectively, as well as a few drivers'
ones may be simplified if rpm_idle() calls rpm_suspend() after 0 has
been returned by the .runtime_idle() callback executed by it.
To reduce overall code bloat, make the changes described above.
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Kevin Hilman <khilman@linaro.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
when suspend, it need check 'udev->actconfig'.
so when process failure, also need check it.
Signed-off-by: Chen Gang <gang.chen@asianux.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch (as1675) removes the CONFIG_USB_SUSPEND option, essentially
replacing it everywhere with CONFIG_PM_RUNTIME (except for one place
in hub.c, where it is replaced with CONFIG_PM because the code needs
to be used in both runtime and system PM). The net result is code
shrinkage and simplification.
There's very little point in keeping CONFIG_USB_SUSPEND because almost
everybody enables it. The few that don't will find that the usbcore
module has gotten somewhat bigger and they will have to take active
measures if they want to prevent hubs from being runtime suspended.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch adds comments on interface driver suspend callback
to emphasize that the failure return value is ignored by
USB core in system sleep context, so do not try to recover
device for this case and let resume/reset_resume callback
handle the suspend failure if needed.
Also kerneldoc for usb_suspend_both() is updated with the
fact.
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull trivial branch from Jiri Kosina:
"Usual stuff -- comment/printk typo fixes, documentation updates, dead
code elimination."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (39 commits)
HOWTO: fix double words typo
x86 mtrr: fix comment typo in mtrr_bp_init
propagate name change to comments in kernel source
doc: Update the name of profiling based on sysfs
treewide: Fix typos in various drivers
treewide: Fix typos in various Kconfig
wireless: mwifiex: Fix typo in wireless/mwifiex driver
messages: i2o: Fix typo in messages/i2o
scripts/kernel-doc: check that non-void fcts describe their return value
Kernel-doc: Convention: Use a "Return" section to describe return values
radeon: Fix typo and copy/paste error in comments
doc: Remove unnecessary declarations from Documentation/accounting/getdelays.c
various: Fix spelling of "asynchronous" in comments.
Fix misspellings of "whether" in comments.
eisa: Fix spelling of "asynchronous".
various: Fix spelling of "registered" in comments.
doc: fix quite a few typos within Documentation
target: iscsi: fix comment typos in target/iscsi drivers
treewide: fix typo of "suport" in various comments and Kconfig
treewide: fix typo of "suppport" in various comments
...
Remove conditional code based on CONFIG_HOTPLUG being false. It's
always on now in preparation of it going away as an option.
Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Greg Kroah-Hartman