On Thursday, September 02, 2010, Alan Stern wrote: > On Wed, 1 Sep 2010, Colin Cross wrote: > > > 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. > > This would work okay if C->power.completion had been initialized to the > completed state during boot, right? > > > 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 | 3 ++- > > 1 files changed, 2 insertions(+), 1 deletions(-) > > > > diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c > > index cb784a0..e159910 100644 > > --- a/drivers/base/power/main.c > > +++ b/drivers/base/power/main.c > > @@ -526,7 +526,8 @@ 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; > > I think it would be better to change device_pm_init() and add a > complete_all(). I agree. Who's writing the patch? Rafael _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
