From 3d46a3cb102b5f43d8ff24fe745cd463f2501de9 Mon Sep 17 00:00:00 2001 From: Colin Cross Date: Wed, 1 Sep 2010 18:35:55 -0700 Subject: [PATCH] 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 --- drivers/base/power/main.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c index 00d0bd8b0d94..17aff79bd329 100644 --- a/drivers/base/power/main.c +++ b/drivers/base/power/main.c @@ -528,7 +528,8 @@ 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.status = DPM_RESUMING; -- 2.34.1