2 * suspend.c - Functions for putting devices to sleep.
4 * Copyright (c) 2003 Patrick Mochel
5 * Copyright (c) 2003 Open Source Development Labs
7 * This file is released under the GPLv2
11 #include <linux/vt_kern.h>
12 #include <linux/device.h>
13 #include <linux/kallsyms.h>
19 * The entries in the dpm_active list are in a depth first order, simply
20 * because children are guaranteed to be discovered after parents, and
21 * are inserted at the back of the list on discovery.
23 * All list on the suspend path are done in reverse order, so we operate
24 * on the leaves of the device tree (or forests, depending on how you want
25 * to look at it ;) first. As nodes are removed from the back of the list,
26 * they are inserted into the front of their destintation lists.
28 * Things are the reverse on the resume path - iterations are done in
29 * forward order, and nodes are inserted at the back of their destination
30 * lists. This way, the ancestors will be accessed before their descendents.
35 * suspend_device - Save state of one device.
37 * @state: Power state device is entering.
40 int suspend_device(struct device * dev, pm_message_t state)
45 if (dev->power.power_state.event) {
46 dev_dbg(dev, "PM: suspend %d-->%d\n",
47 dev->power.power_state.event, state.event);
49 if (dev->power.pm_parent
50 && dev->power.pm_parent->power.power_state.event) {
52 "PM: suspend %d->%d, parent %s already %d\n",
53 dev->power.power_state.event, state.event,
54 dev->power.pm_parent->bus_id,
55 dev->power.pm_parent->power.power_state.event);
58 dev->power.prev_state = dev->power.power_state;
60 if (dev->bus && dev->bus->suspend && !dev->power.power_state.event) {
61 dev_dbg(dev, "suspending\n");
62 error = dev->bus->suspend(dev, state);
63 suspend_report_result(dev->bus->suspend, error);
70 * device_suspend - Save state and stop all devices in system.
71 * @state: Power state to put each device in.
73 * Walk the dpm_active list, call ->suspend() for each device, and move
75 * Check the return value for each. If it returns 0, then we move the
76 * the device to the dpm_off list. If it returns -EAGAIN, we move it to
77 * the dpm_off_irq list. If we get a different error, try and back out.
79 * If we hit a failure with any of the devices, call device_resume()
80 * above to bring the suspended devices back to life.
84 int device_suspend(pm_message_t state)
88 if (!is_console_suspend_safe())
93 while (!list_empty(&dpm_active) && error == 0) {
94 struct list_head * entry = dpm_active.prev;
95 struct device * dev = to_device(entry);
100 error = suspend_device(dev, state);
104 /* Check if the device got removed */
105 if (!list_empty(&dev->power.entry)) {
106 /* Move it to the dpm_off or dpm_off_irq list */
108 list_del(&dev->power.entry);
109 list_add(&dev->power.entry, &dpm_off);
110 } else if (error == -EAGAIN) {
111 list_del(&dev->power.entry);
112 list_add(&dev->power.entry, &dpm_off_irq);
117 printk(KERN_ERR "Could not suspend device %s: "
118 "error %d\n", kobject_name(&dev->kobj), error);
123 /* we failed... before resuming, bring back devices from
124 * dpm_off_irq list back to main dpm_off list, we do want
125 * to call resume() on them, in case they partially suspended
126 * despite returning -EAGAIN
128 while (!list_empty(&dpm_off_irq)) {
129 struct list_head * entry = dpm_off_irq.next;
131 list_add(entry, &dpm_off);
139 EXPORT_SYMBOL_GPL(device_suspend);
143 * device_power_down - Shut down special devices.
144 * @state: Power state to enter.
146 * Walk the dpm_off_irq list, calling ->power_down() for each device that
147 * couldn't power down the device with interrupts enabled. When we're
148 * done, power down system devices.
151 int device_power_down(pm_message_t state)
156 list_for_each_entry_reverse(dev, &dpm_off_irq, power.entry) {
157 if ((error = suspend_device(dev, state)))
162 if ((error = sysdev_suspend(state)))
167 printk(KERN_ERR "Could not power down device %s: "
168 "error %d\n", kobject_name(&dev->kobj), error);
173 EXPORT_SYMBOL_GPL(device_power_down);
175 void __suspend_report_result(const char *function, void *fn, int ret)
178 printk(KERN_ERR "%s(): ", function);
179 print_fn_descriptor_symbol("%s() returns ", (unsigned long)fn);
183 EXPORT_SYMBOL_GPL(__suspend_report_result);