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authorRafael J. Wysocki <rjw@sisk.pl>2011-05-17 23:26:00 +0200
committerRafael J. Wysocki <rjw@sisk.pl>2011-05-17 23:26:00 +0200
commit91e7c75ba93c48a82670d630b9daac92ff70095d (patch)
treeb44ac3dca1d03cce99cccc3f4ce55d4b5475d373 /include/linux/pm.h
parentc650da23d59d2c82307380414606774c6d49b8bd (diff)
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PM: Allow drivers to allocate memory from .prepare() callbacks safely
If device drivers allocate substantial amounts of memory (above 1 MB) in their hibernate .freeze() callbacks (or in their legacy suspend callbcks during hibernation), the subsequent creation of hibernate image may fail due to the lack of memory. This is the case, because the drivers' .freeze() callbacks are executed after the hibernate memory preallocation has been carried out and the preallocated amount of memory may be too small to cover the new driver allocations. Unfortunately, the drivers' .prepare() callbacks also are executed after the hibernate memory preallocation has completed, so they are not suitable for allocating additional memory either. Thus the only way a driver can safely allocate memory during hibernation is to use a hibernate/suspend notifier. However, the notifiers are called before the freezing of user space and the drivers wanting to use them for allocating additional memory may not know how much memory needs to be allocated at that point. To let device drivers overcome this difficulty rework the hibernation sequence so that the memory preallocation is carried out after the drivers' .prepare() callbacks have been executed, so that the .prepare() callbacks can be used for allocating additional memory to be used by the drivers' .freeze() callbacks. Update documentation to match the new behavior of the code. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Diffstat (limited to 'include/linux/pm.h')
-rw-r--r--include/linux/pm.h4
1 files changed, 4 insertions, 0 deletions
diff --git a/include/linux/pm.h b/include/linux/pm.h
index 3cc3e7e589f0..dce7c7148771 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -533,10 +533,14 @@ struct dev_power_domain {
extern void device_pm_lock(void);
extern void dpm_resume_noirq(pm_message_t state);
extern void dpm_resume_end(pm_message_t state);
+extern void dpm_resume(pm_message_t state);
+extern void dpm_complete(pm_message_t state);
extern void device_pm_unlock(void);
extern int dpm_suspend_noirq(pm_message_t state);
extern int dpm_suspend_start(pm_message_t state);
+extern int dpm_suspend(pm_message_t state);
+extern int dpm_prepare(pm_message_t state);
extern void __suspend_report_result(const char *function, void *fn, int ret);