82428b62aa
This patch includes various tweaks in the messaging that appears during
system pm state transitions:
* Warn about certain illegal calls in the device tree, like resuming
child before parent or suspending parent before child. This could
happen easily enough through sysfs, or in some cases when drivers
use device_pm_set_parent().
* Be more consistent about dev_dbg() tracing ... do it for resume() and
shutdown() too, and never if the driver doesn't have that method.
* Say which type of system sleep state is being entered.
Except for the warnings, these only affect debug messaging.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
157 lines
4 KiB
C
157 lines
4 KiB
C
/*
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* suspend.c - Functions for putting devices to sleep.
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*
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* Copyright (c) 2003 Patrick Mochel
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* Copyright (c) 2003 Open Source Development Labs
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*
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* This file is released under the GPLv2
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*
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*/
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#include <linux/device.h>
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#include "power.h"
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extern int sysdev_suspend(pm_message_t state);
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/*
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* The entries in the dpm_active list are in a depth first order, simply
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* because children are guaranteed to be discovered after parents, and
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* are inserted at the back of the list on discovery.
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*
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* All list on the suspend path are done in reverse order, so we operate
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* on the leaves of the device tree (or forests, depending on how you want
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* to look at it ;) first. As nodes are removed from the back of the list,
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* they are inserted into the front of their destintation lists.
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*
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* Things are the reverse on the resume path - iterations are done in
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* forward order, and nodes are inserted at the back of their destination
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* lists. This way, the ancestors will be accessed before their descendents.
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*/
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/**
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* suspend_device - Save state of one device.
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* @dev: Device.
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* @state: Power state device is entering.
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*/
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int suspend_device(struct device * dev, pm_message_t state)
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{
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int error = 0;
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if (dev->power.power_state) {
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dev_dbg(dev, "PM: suspend %d-->%d\n",
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dev->power.power_state, state);
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}
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if (dev->power.pm_parent
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&& dev->power.pm_parent->power.power_state) {
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dev_err(dev,
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"PM: suspend %d->%d, parent %s already %d\n",
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dev->power.power_state, state,
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dev->power.pm_parent->bus_id,
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dev->power.pm_parent->power.power_state);
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}
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dev->power.prev_state = dev->power.power_state;
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if (dev->bus && dev->bus->suspend && !dev->power.power_state) {
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dev_dbg(dev, "suspending\n");
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error = dev->bus->suspend(dev, state);
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}
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return error;
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}
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/**
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* device_suspend - Save state and stop all devices in system.
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* @state: Power state to put each device in.
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*
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* Walk the dpm_active list, call ->suspend() for each device, and move
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* it to dpm_off.
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* Check the return value for each. If it returns 0, then we move the
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* the device to the dpm_off list. If it returns -EAGAIN, we move it to
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* the dpm_off_irq list. If we get a different error, try and back out.
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*
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* If we hit a failure with any of the devices, call device_resume()
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* above to bring the suspended devices back to life.
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*
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*/
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int device_suspend(pm_message_t state)
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{
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int error = 0;
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down(&dpm_sem);
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down(&dpm_list_sem);
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while (!list_empty(&dpm_active) && error == 0) {
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struct list_head * entry = dpm_active.prev;
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struct device * dev = to_device(entry);
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get_device(dev);
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up(&dpm_list_sem);
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error = suspend_device(dev, state);
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down(&dpm_list_sem);
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/* Check if the device got removed */
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if (!list_empty(&dev->power.entry)) {
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/* Move it to the dpm_off or dpm_off_irq list */
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if (!error) {
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list_del(&dev->power.entry);
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list_add(&dev->power.entry, &dpm_off);
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} else if (error == -EAGAIN) {
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list_del(&dev->power.entry);
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list_add(&dev->power.entry, &dpm_off_irq);
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error = 0;
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}
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}
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if (error)
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printk(KERN_ERR "Could not suspend device %s: "
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"error %d\n", kobject_name(&dev->kobj), error);
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put_device(dev);
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}
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up(&dpm_list_sem);
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if (error)
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dpm_resume();
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up(&dpm_sem);
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return error;
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}
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EXPORT_SYMBOL_GPL(device_suspend);
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/**
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* device_power_down - Shut down special devices.
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* @state: Power state to enter.
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*
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* Walk the dpm_off_irq list, calling ->power_down() for each device that
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* couldn't power down the device with interrupts enabled. When we're
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* done, power down system devices.
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*/
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int device_power_down(pm_message_t state)
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{
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int error = 0;
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struct device * dev;
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list_for_each_entry_reverse(dev, &dpm_off_irq, power.entry) {
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if ((error = suspend_device(dev, state)))
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break;
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}
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if (error)
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goto Error;
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if ((error = sysdev_suspend(state)))
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goto Error;
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Done:
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return error;
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Error:
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printk(KERN_ERR "Could not power down device %s: "
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"error %d\n", kobject_name(&dev->kobj), error);
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dpm_power_up();
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goto Done;
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}
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EXPORT_SYMBOL_GPL(device_power_down);
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