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@xxxxxxxxxxx>
---
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 cb784a0..b1b4029 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -63,6 +63,7 @@ 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);
}
--
1.7.1
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