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author | Colin Cross <ccross@android.com> | 2010-09-03 01:24:07 +0200 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-09-26 17:18:37 -0700 |
commit | 2af3495b6359c30740b31175aa818f600f5b8bb9 (patch) | |
tree | 809c28786394e12b6310fc8687a692e3828176e1 | |
parent | bf818d9482431477a787aba2704c8cc48e226703 (diff) | |
download | kernel-crypto-2af3495b6359c30740b31175aa818f600f5b8bb9.tar.gz kernel-crypto-2af3495b6359c30740b31175aa818f600f5b8bb9.tar.xz kernel-crypto-2af3495b6359c30740b31175aa818f600f5b8bb9.zip |
PM: Prevent waiting forever on asynchronous resume after failing suspend
commit 152e1d592071c8b312bb898bc1118b64e4aea535 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-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 941fcb87e52..cb1cedc69c9 100644 --- a/drivers/base/power/main.c +++ b/drivers/base/power/main.c @@ -59,6 +59,7 @@ void device_pm_init(struct device *dev) { dev->power.status = DPM_ON; init_completion(&dev->power.completion); + complete_all(&dev->power.completion); pm_runtime_init(dev); } |