diff options
author | Colin Cross <ccross@android.com> | 2010-09-02 19:24:07 -0400 |
---|---|---|
committer | Rafael J. Wysocki <rjw@sisk.pl> | 2010-09-08 18:49:43 -0400 |
commit | 152e1d592071c8b312bb898bc1118b64e4aea535 (patch) | |
tree | 4e26f4a54914543c42b08b5e553ed2d671ba3fe0 | |
parent | d56557af19867edb8c0e96f8e26399698a08857f (diff) |
PM: Prevent waiting forever on asynchronous resume after failing suspend
During suspend, the power.completion is expected to be set when a
device has not yet started suspending. Set it on init to fix a
corner case where a device is resumed when its parent has never
suspended.
Consider three drivers, A, B, and C. The parent of A is C, and C
has async_suspend set. On boot, C->power.completion is initialized
to 0.
During the first suspend:
suspend_devices_and_enter(...)
dpm_resume(...)
device_suspend(A)
device_suspend(B) returns error, aborts suspend
dpm_resume_end(...)
dpm_resume(...)
device_resume(A)
dpm_wait(A->parent == C)
wait_for_completion(C->power.completion)
The wait_for_completion will never complete, because
complete_all(C->power.completion) will only be called from
device_suspend(C) or device_resume(C), neither of which is called
if suspend is aborted before C.
After a successful suspend->resume cycle, where B doesn't abort
suspend, C->power.completion is left in the completed state by the
call to device_resume(C), and the same call path will work if B
aborts suspend.
Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
-rw-r--r-- | drivers/base/power/main.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c index 5419a49ff135..276d5a701dc3 100644 --- a/drivers/base/power/main.c +++ b/drivers/base/power/main.c | |||
@@ -59,6 +59,7 @@ void device_pm_init(struct device *dev) | |||
59 | { | 59 | { |
60 | dev->power.status = DPM_ON; | 60 | dev->power.status = DPM_ON; |
61 | init_completion(&dev->power.completion); | 61 | init_completion(&dev->power.completion); |
62 | complete_all(&dev->power.completion); | ||
62 | dev->power.wakeup_count = 0; | 63 | dev->power.wakeup_count = 0; |
63 | pm_runtime_init(dev); | 64 | pm_runtime_init(dev); |
64 | } | 65 | } |