diff options
| author | Colin Cross <ccross@android.com> | 2010-09-01 18:35:55 -0700 |
|---|---|---|
| committer | Colin Cross <ccross@android.com> | 2011-06-14 09:09:35 -0700 |
| commit | fa92a3d6959546baa27e892188d3e9bb79c31741 (patch) | |
| tree | db64b42fee24086a8da5ec2aed4dee8167598210 /drivers/base | |
| parent | 435aacd2a0cf0fc6402719fb69a3fac614686347 (diff) | |
PM: Prevent waiting forever on asynchronous resume after abort
Only wait on a parent device during resume if the parent device is
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>
Diffstat (limited to 'drivers/base')
| -rw-r--r-- | drivers/base/power/main.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c index c31045e8938e..111a77dba092 100644 --- a/drivers/base/power/main.c +++ b/drivers/base/power/main.c @@ -512,7 +512,8 @@ static int device_resume(struct device *dev, pm_message_t state, bool async) TRACE_DEVICE(dev); TRACE_RESUME(0); - dpm_wait(dev->parent, async); + if (dev->parent && dev->parent->power.status >= DPM_OFF) + dpm_wait(dev->parent, async); device_lock(dev); dev->power.in_suspend = false; |