diff options
author | Colin Cross <ccross@android.com> | 2010-09-01 18:35:55 -0700 |
---|---|---|
committer | Dan Willemsen <dwillemsen@nvidia.com> | 2011-11-30 21:38:20 -0800 |
commit | d0add622e869a057c793165bddfb4b8c5d7ced36 (patch) | |
tree | c7e078800b572567672a76d07a995de941000870 /drivers/base/power/main.c | |
parent | 4821b01af559f225600d4c3b303d89f9ca4f765b (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/power/main.c')
-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 5e576466a189..cb55a9609207 100644 --- a/drivers/base/power/main.c +++ b/drivers/base/power/main.c @@ -514,7 +514,8 @@ 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); /* |