[PATCH] revert "swsusp add check for suspension of X controlled devices"
[linux-2.6.git] / drivers / base / power / suspend.c
1 /*
2  * suspend.c - Functions for putting devices to sleep.
3  *
4  * Copyright (c) 2003 Patrick Mochel
5  * Copyright (c) 2003 Open Source Development Labs
6  *
7  * This file is released under the GPLv2
8  *
9  */
10
11 #include <linux/device.h>
12 #include <linux/kallsyms.h>
13 #include <linux/pm.h>
14 #include "../base.h"
15 #include "power.h"
16
17 /*
18  * The entries in the dpm_active list are in a depth first order, simply
19  * because children are guaranteed to be discovered after parents, and
20  * are inserted at the back of the list on discovery.
21  *
22  * All list on the suspend path are done in reverse order, so we operate
23  * on the leaves of the device tree (or forests, depending on how you want
24  * to look at it ;) first. As nodes are removed from the back of the list,
25  * they are inserted into the front of their destintation lists.
26  *
27  * Things are the reverse on the resume path - iterations are done in
28  * forward order, and nodes are inserted at the back of their destination
29  * lists. This way, the ancestors will be accessed before their descendents.
30  */
31
32
33 /**
34  *      suspend_device - Save state of one device.
35  *      @dev:   Device.
36  *      @state: Power state device is entering.
37  */
38
39 int suspend_device(struct device * dev, pm_message_t state)
40 {
41         int error = 0;
42
43         down(&dev->sem);
44         if (dev->power.power_state.event) {
45                 dev_dbg(dev, "PM: suspend %d-->%d\n",
46                         dev->power.power_state.event, state.event);
47         }
48         if (dev->power.pm_parent
49                         && dev->power.pm_parent->power.power_state.event) {
50                 dev_err(dev,
51                         "PM: suspend %d->%d, parent %s already %d\n",
52                         dev->power.power_state.event, state.event,
53                         dev->power.pm_parent->bus_id,
54                         dev->power.pm_parent->power.power_state.event);
55         }
56
57         dev->power.prev_state = dev->power.power_state;
58
59         if (dev->bus && dev->bus->suspend && !dev->power.power_state.event) {
60                 dev_dbg(dev, "suspending\n");
61                 error = dev->bus->suspend(dev, state);
62                 suspend_report_result(dev->bus->suspend, error);
63         }
64         up(&dev->sem);
65         return error;
66 }
67
68
69 /**
70  *      device_suspend - Save state and stop all devices in system.
71  *      @state:         Power state to put each device in.
72  *
73  *      Walk the dpm_active list, call ->suspend() for each device, and move
74  *      it to dpm_off.
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.
78  *
79  *      If we hit a failure with any of the devices, call device_resume()
80  *      above to bring the suspended devices back to life.
81  *
82  */
83
84 int device_suspend(pm_message_t state)
85 {
86         int error = 0;
87
88         down(&dpm_sem);
89         down(&dpm_list_sem);
90         while (!list_empty(&dpm_active) && error == 0) {
91                 struct list_head * entry = dpm_active.prev;
92                 struct device * dev = to_device(entry);
93
94                 get_device(dev);
95                 up(&dpm_list_sem);
96
97                 error = suspend_device(dev, state);
98
99                 down(&dpm_list_sem);
100
101                 /* Check if the device got removed */
102                 if (!list_empty(&dev->power.entry)) {
103                         /* Move it to the dpm_off or dpm_off_irq list */
104                         if (!error) {
105                                 list_del(&dev->power.entry);
106                                 list_add(&dev->power.entry, &dpm_off);
107                         } else if (error == -EAGAIN) {
108                                 list_del(&dev->power.entry);
109                                 list_add(&dev->power.entry, &dpm_off_irq);
110                                 error = 0;
111                         }
112                 }
113                 if (error)
114                         printk(KERN_ERR "Could not suspend device %s: "
115                                 "error %d\n", kobject_name(&dev->kobj), error);
116                 put_device(dev);
117         }
118         up(&dpm_list_sem);
119         if (error) {
120                 /* we failed... before resuming, bring back devices from
121                  * dpm_off_irq list back to main dpm_off list, we do want
122                  * to call resume() on them, in case they partially suspended
123                  * despite returning -EAGAIN
124                  */
125                 while (!list_empty(&dpm_off_irq)) {
126                         struct list_head * entry = dpm_off_irq.next;
127                         list_del(entry);
128                         list_add(entry, &dpm_off);
129                 }
130                 dpm_resume();
131         }
132         up(&dpm_sem);
133         return error;
134 }
135
136 EXPORT_SYMBOL_GPL(device_suspend);
137
138
139 /**
140  *      device_power_down - Shut down special devices.
141  *      @state:         Power state to enter.
142  *
143  *      Walk the dpm_off_irq list, calling ->power_down() for each device that
144  *      couldn't power down the device with interrupts enabled. When we're
145  *      done, power down system devices.
146  */
147
148 int device_power_down(pm_message_t state)
149 {
150         int error = 0;
151         struct device * dev;
152
153         list_for_each_entry_reverse(dev, &dpm_off_irq, power.entry) {
154                 if ((error = suspend_device(dev, state)))
155                         break;
156         }
157         if (error)
158                 goto Error;
159         if ((error = sysdev_suspend(state)))
160                 goto Error;
161  Done:
162         return error;
163  Error:
164         printk(KERN_ERR "Could not power down device %s: "
165                 "error %d\n", kobject_name(&dev->kobj), error);
166         dpm_power_up();
167         goto Done;
168 }
169
170 EXPORT_SYMBOL_GPL(device_power_down);
171
172 void __suspend_report_result(const char *function, void *fn, int ret)
173 {
174         if (ret) {
175                 printk(KERN_ERR "%s(): ", function);
176                 print_fn_descriptor_symbol("%s() returns ", (unsigned long)fn);
177                 printk("%d\n", ret);
178         }
179 }
180 EXPORT_SYMBOL_GPL(__suspend_report_result);