linux/drivers/base/power/suspend.c
Rafael J. Wysocki 43a49f8baa PM: Do not check parent state in suspend and resume core code
The checks if the device's parent is in the right state done in
drivers/base/power/suspend.c and drivers/base/power/resume.c serve no particular
purpose, since if the parent is in a wrong power state, the device's suspend or
resume callbacks are supposed to return an error anyway.  Moreover, they are
also useless from the sanity checking point of view, because they rely on the
code being checked to set dev->parent->power.power_state.event appropriately,
which need not happen if that code is buggy.  For these reasons they can be
removed.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11 16:09:02 -07:00

210 lines
5.4 KiB
C

/*
* suspend.c - Functions for putting devices to sleep.
*
* Copyright (c) 2003 Patrick Mochel
* Copyright (c) 2003 Open Source Development Labs
*
* This file is released under the GPLv2
*
*/
#include <linux/device.h>
#include <linux/kallsyms.h>
#include <linux/pm.h>
#include "../base.h"
#include "power.h"
/*
* The entries in the dpm_active list are in a depth first order, simply
* because children are guaranteed to be discovered after parents, and
* are inserted at the back of the list on discovery.
*
* All list on the suspend path are done in reverse order, so we operate
* on the leaves of the device tree (or forests, depending on how you want
* to look at it ;) first. As nodes are removed from the back of the list,
* they are inserted into the front of their destintation lists.
*
* Things are the reverse on the resume path - iterations are done in
* forward order, and nodes are inserted at the back of their destination
* lists. This way, the ancestors will be accessed before their descendents.
*/
static inline char *suspend_verb(u32 event)
{
switch (event) {
case PM_EVENT_SUSPEND: return "suspend";
case PM_EVENT_FREEZE: return "freeze";
case PM_EVENT_PRETHAW: return "prethaw";
default: return "(unknown suspend event)";
}
}
static void
suspend_device_dbg(struct device *dev, pm_message_t state, char *info)
{
dev_dbg(dev, "%s%s%s\n", info, suspend_verb(state.event),
((state.event == PM_EVENT_SUSPEND) && device_may_wakeup(dev)) ?
", may wakeup" : "");
}
/**
* suspend_device - Save state of one device.
* @dev: Device.
* @state: Power state device is entering.
*/
int suspend_device(struct device * dev, pm_message_t state)
{
int error = 0;
down(&dev->sem);
if (dev->power.power_state.event) {
dev_dbg(dev, "PM: suspend %d-->%d\n",
dev->power.power_state.event, state.event);
}
if (dev->class && dev->class->suspend) {
suspend_device_dbg(dev, state, "class ");
error = dev->class->suspend(dev, state);
suspend_report_result(dev->class->suspend, error);
}
if (!error && dev->type && dev->type->suspend) {
suspend_device_dbg(dev, state, "type ");
error = dev->type->suspend(dev, state);
suspend_report_result(dev->type->suspend, error);
}
if (!error && dev->bus && dev->bus->suspend) {
suspend_device_dbg(dev, state, "");
error = dev->bus->suspend(dev, state);
suspend_report_result(dev->bus->suspend, error);
}
up(&dev->sem);
return error;
}
/*
* This is called with interrupts off, only a single CPU
* running. We can't acquire a mutex or semaphore (and we don't
* need the protection)
*/
static int suspend_device_late(struct device *dev, pm_message_t state)
{
int error = 0;
if (dev->bus && dev->bus->suspend_late) {
suspend_device_dbg(dev, state, "LATE ");
error = dev->bus->suspend_late(dev, state);
suspend_report_result(dev->bus->suspend_late, error);
}
return error;
}
/**
* device_suspend - Save state and stop all devices in system.
* @state: Power state to put each device in.
*
* Walk the dpm_active list, call ->suspend() for each device, and move
* it to the dpm_off list.
*
* (For historical reasons, if it returns -EAGAIN, that used to mean
* that the device would be called again with interrupts disabled.
* These days, we use the "suspend_late()" callback for that, so we
* print a warning and consider it an error).
*
* If we get a different error, try and back out.
*
* If we hit a failure with any of the devices, call device_resume()
* above to bring the suspended devices back to life.
*
*/
int device_suspend(pm_message_t state)
{
int error = 0;
might_sleep();
mutex_lock(&dpm_mtx);
mutex_lock(&dpm_list_mtx);
while (!list_empty(&dpm_active) && error == 0) {
struct list_head * entry = dpm_active.prev;
struct device * dev = to_device(entry);
get_device(dev);
mutex_unlock(&dpm_list_mtx);
error = suspend_device(dev, state);
mutex_lock(&dpm_list_mtx);
/* Check if the device got removed */
if (!list_empty(&dev->power.entry)) {
/* Move it to the dpm_off list */
if (!error)
list_move(&dev->power.entry, &dpm_off);
}
if (error)
printk(KERN_ERR "Could not suspend device %s: "
"error %d%s\n",
kobject_name(&dev->kobj), error,
error == -EAGAIN ? " (please convert to suspend_late)" : "");
put_device(dev);
}
mutex_unlock(&dpm_list_mtx);
if (error)
dpm_resume();
mutex_unlock(&dpm_mtx);
return error;
}
EXPORT_SYMBOL_GPL(device_suspend);
/**
* device_power_down - Shut down special devices.
* @state: Power state to enter.
*
* Walk the dpm_off_irq list, calling ->power_down() for each device that
* couldn't power down the device with interrupts enabled. When we're
* done, power down system devices.
*/
int device_power_down(pm_message_t state)
{
int error = 0;
struct device * dev;
while (!list_empty(&dpm_off)) {
struct list_head * entry = dpm_off.prev;
dev = to_device(entry);
error = suspend_device_late(dev, state);
if (error)
goto Error;
list_move(&dev->power.entry, &dpm_off_irq);
}
error = sysdev_suspend(state);
Done:
return error;
Error:
printk(KERN_ERR "Could not power down device %s: "
"error %d\n", kobject_name(&dev->kobj), error);
dpm_power_up();
goto Done;
}
EXPORT_SYMBOL_GPL(device_power_down);
void __suspend_report_result(const char *function, void *fn, int ret)
{
if (ret) {
printk(KERN_ERR "%s(): ", function);
print_fn_descriptor_symbol("%s() returns ", (unsigned long)fn);
printk("%d\n", ret);
}
}
EXPORT_SYMBOL_GPL(__suspend_report_result);