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[PATCH] Driver Core: remove driver model detach_state 

The driver model has a "detach_state" mechanism that:

 - Has never been used by any in-kernel drive;
 - Is superfluous, since driver remove() methods can do the same thing;
 - Became buggy when the suspend() parameter changed semantics and type;
 - Could self-deadlock when called from certain suspend contexts;
 - Is effectively wasted documentation, object code, and headspace.

This removes that "detach_state" mechanism; net code shrink, as well
as a per-device saving in the driver model and sysfs.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
David Brownell 2005-05-12 12:06:27 -07:00 committed by Greg KH
parent 82428b62aa
commit 0b405a0f7e
10 changed files with 5 additions and 113 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
Documentation/filesystems/sysfs-pci.txt
View File

@ -7,7 +7,6 @@ that support it. For example, a given bus might look like this:
|-- 0000:17:00.0
| |-- class
| |-- config
| |-- detach_state
| |-- device
| |-- irq
| |-- local_cpus
@ -19,7 +18,7 @@ that support it. For example, a given bus might look like this:
| |-- subsystem_device
| |-- subsystem_vendor
| `-- vendor
`-- detach_state
`-- ...
The topmost element describes the PCI domain and bus number. In this case,
the domain number is 0000 and the bus number is 17 (both values are in hex).
@ -31,7 +30,6 @@ files, each with their own function.
---- --------
class PCI class (ascii, ro)
config PCI config space (binary, rw)
detach_state connection status (bool, rw)
device PCI device (ascii, ro)
irq IRQ number (ascii, ro)
local_cpus nearby CPU mask (cpumask, ro)
@ -85,4 +83,4 @@ useful return codes should be provided.
Legacy resources are protected by the HAVE_PCI_LEGACY define. Platforms
wishing to support legacy functionality should define it and provide
pci_legacy_read, pci_legacy_write and pci_mmap_legacy_page_range functions.
pci_legacy_read, pci_legacy_write and pci_mmap_legacy_page_range functions.

21
Documentation/power/devices.txt
View File

@ -207,27 +207,6 @@ SYSTEM_SHUTDOWN, I do not understand this one too much. probably event
#READY_AFTER_RESUME
#
Driver Detach Power Management
The kernel now supports the ability to place a device in a low-power
state when it is detached from its driver, which happens when its
module is removed.
Each device contains a 'detach_state' file in its sysfs directory
which can be used to control this state. Reading from this file
displays what the current detach state is set to. This is 0 (On) by
default. A user may write a positive integer value to this file in the
range of 1-4 inclusive.
A value of 1-3 will indicate the device should be placed in that
low-power state, which will cause ->suspend() to be called for that
device. A value of 4 indicates that the device should be shutdown, so
->shutdown() will be called for that device.
The driver is responsible for reinitializing the device when the
module is re-inserted during it's ->probe() (or equivalent) method.
The driver core will not call any extra functions when binding the
device to the driver.
pm_message_t meaning

4
Documentation/powerpc/hvcs.txt
View File

@ -347,8 +347,8 @@ address that is created by firmware. An example vty-server sysfs entry
looks like the following:
Pow5:/sys/bus/vio/drivers/hvcs/30000004 # ls
. current_vty devspec name partner_vtys
.. detach_state index partner_clcs vterm_state
. current_vty devspec name partner_vtys
.. index partner_clcs vterm_state
Each entry is provided, by default with a "name" attribute. Reading the
"name" attribute will reveal the device type as shown in the following

2
drivers/base/Makefile
View File

@ -1,6 +1,6 @@
# Makefile for the Linux device tree
obj-y := core.o sys.o interface.o bus.o \
obj-y := core.o sys.o bus.o \
driver.o class.o class_simple.o platform.o \
cpu.o firmware.o init.o map.o dmapool.o \
attribute_container.o transport_class.o

1
drivers/base/bus.c
View File

@ -390,7 +390,6 @@ void device_release_driver(struct device * dev)
sysfs_remove_link(&drv->kobj, kobject_name(&dev->kobj));
sysfs_remove_link(&dev->kobj, "driver");
list_del_init(&dev->driver_list);
device_detach_shutdown(dev);
if (drv->remove)
drv->remove(dev);
dev->driver = NULL;

3
drivers/base/core.c
View File

@ -31,8 +31,6 @@ int (*platform_notify_remove)(struct device * dev) = NULL;
#define to_dev(obj) container_of(obj, struct device, kobj)
#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
extern struct attribute * dev_default_attrs[];
static ssize_t
dev_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
{
@ -89,7 +87,6 @@ static void device_release(struct kobject * kobj)
static struct kobj_type ktype_device = {
.release = device_release,
.sysfs_ops = &dev_sysfs_ops,
.default_attrs = dev_default_attrs,
};

51
drivers/base/interface.c
View File

@ -1,51 +0,0 @@
/*
* drivers/base/interface.c - common driverfs interface that's exported to
* the world for all devices.
*
* Copyright (c) 2002-3 Patrick Mochel
* Copyright (c) 2002-3 Open Source Development Labs
*
* This file is released under the GPLv2
*
*/
#include <linux/device.h>
#include <linux/err.h>
#include <linux/stat.h>
#include <linux/string.h>
/**
* detach_state - control the default power state for the device.
*
* This is the state the device enters when it's driver module is
* unloaded. The value is an unsigned integer, in the range of 0-4.
* '0' indicates 'On', so no action will be taken when the driver is
* unloaded. This is the default behavior.
* '4' indicates 'Off', meaning the driver core will call the driver's
* shutdown method to quiesce the device.
* 1-3 indicate a low-power state for the device to enter via the
* driver's suspend method.
*/
static ssize_t detach_show(struct device * dev, char * buf)
{
return sprintf(buf, "%u\n", dev->detach_state);
}
static ssize_t detach_store(struct device * dev, const char * buf, size_t n)
{
u32 state;
state = simple_strtoul(buf, NULL, 10);
if (state > 4)
return -EINVAL;
dev->detach_state = state;
return n;
}
static DEVICE_ATTR(detach_state, 0644, detach_show, detach_store);
struct attribute * dev_default_attrs[] = {
&dev_attr_detach_state.attr,
NULL,
};

11
drivers/base/power/power.h
View File

@ -1,18 +1,7 @@
enum {
DEVICE_PM_ON,
DEVICE_PM1,
DEVICE_PM2,
DEVICE_PM3,
DEVICE_PM_OFF,
};
/*
* shutdown.c
*/
extern int device_detach_shutdown(struct device *);
extern void device_shutdown(void);

16
drivers/base/power/shutdown.c
View File

@ -19,22 +19,6 @@
extern struct subsystem devices_subsys;
int device_detach_shutdown(struct device * dev)
{
if (!dev->detach_state)
return 0;
if (dev->detach_state == DEVICE_PM_OFF) {
if (dev->driver && dev->driver->shutdown) {
dev_dbg(dev, "shutdown\n");
dev->driver->shutdown(dev);
}
return 0;
}
return dpm_runtime_suspend(dev, dev->detach_state);
}
/**
* We handle system devices differently - we suspend and shut them
* down last and resume them first. That way, we don't do anything stupid like

3
include/linux/device.h
View File

@ -273,9 +273,6 @@ struct device {
BIOS data relevant to device) */
struct dev_pm_info power;
u32 detach_state; /* State to enter when device is
detached from its driver. */
u64 *dma_mask; /* dma mask (if dma'able device) */
u64 coherent_dma_mask;/* Like dma_mask, but for
alloc_coherent mappings as