On Monday, June 29, 2015 09:56:18 PM Rafael J. Wysocki wrote: > On Tuesday, June 30, 2015 12:24:14 AM Nitish Ambastha wrote: > > Prevent tight loop for suspend-resume when some > > devices failed to suspend > > If some devices failed to suspend, we monitor this > > error in try_to_suspend(). pm_suspend() is already > > an 'int' returning function, how about checking return > > from pm_suspend() before queueing suspend again? > > > > For devices which do not register for pending events, > > this will prevent tight loop for suspend-resume in > > suspend abort scenarios due to device suspend failures
Having said the below I'm not sure why the current code doesn't cover this for you? That would be the final_count == initial_count case, no? > > > > Signed-off-by: Nitish Ambastha <[email protected]> > > --- > > v2: Rearranged code to make wait entry shared with > > existing one as suggested by Pavel Machek <[email protected]> > > Corrected log level from pr_info to pr_err for failure log > > Added return check for hibernate() > > > > kernel/power/autosleep.c | 23 ++++++++++++++++------- > > 1 file changed, 16 insertions(+), 7 deletions(-) > > > > diff --git a/kernel/power/autosleep.c b/kernel/power/autosleep.c > > index 9012ecf..1a86698 100644 > > --- a/kernel/power/autosleep.c > > +++ b/kernel/power/autosleep.c > > @@ -26,6 +26,7 @@ static struct wakeup_source *autosleep_ws; > > static void try_to_suspend(struct work_struct *work) > > { > > unsigned int initial_count, final_count; > > + int error = 0; > > The initial value is not needed. > > > > > if (!pm_get_wakeup_count(&initial_count, true)) > > goto out; > > @@ -43,22 +44,30 @@ static void try_to_suspend(struct work_struct *work) > > return; > > } > > if (autosleep_state >= PM_SUSPEND_MAX) > > - hibernate(); > > + error = hibernate(); > > else > > - pm_suspend(autosleep_state); > > + error = pm_suspend(autosleep_state); > > I'd prefer to write that as > > error = autosleep_state < PM_SUSPEND_MAX ? > pm_suspend(autosleep_state) : hibernate(); > > > > > mutex_unlock(&autosleep_lock); > > > > + if (error) { > > + pr_err("PM: suspend returned (%d)\n", error); > > There is a debug message printed for that in the device suspend code, do we > need one more here? > > > + goto wait; > > + } > > + > > if (!pm_get_wakeup_count(&final_count, false)) > > goto out; > > > > + if (final_count != initial_count) > > + goto out; > > + > > + wait: > > /* > > - * If the wakeup occured for an unknown reason, wait to prevent the > > - * system from trying to suspend and waking up in a tight loop. > > + * If some devices failed to suspend or if the wakeup ocurred > > + * for an unknown reason, wait to prevent the system from > > + * trying to suspend and waking up in a tight loop. > > */ > > - if (final_count == initial_count) > > - schedule_timeout_uninterruptible(HZ / 2); > > - > > + schedule_timeout_uninterruptible(HZ / 2); > > out: > > queue_up_suspend_work(); > > I'd arrange it this way: > > if (error || pm_get_wakeup_count(&final_count, false) > || final_count == initial_count) > schedule_timeout_uninterruptible(HZ / 2); > > out: > queue_up_suspend_work(); > > } > > > > -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
