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Subject[PATCHv2 1/1] kernel/power/autosleep.c: check for pm_suspend() return before queueing suspend again
Date
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

Signed-off-by: Nitish Ambastha <nitish.a@samsung.com>
---
v2: Rearranged code to make wait entry shared with
existing one as suggested by Pavel Machek <pavel@ucw.cz>
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;

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);

mutex_unlock(&autosleep_lock);

+ if (error) {
+ pr_err("PM: suspend returned (%d)\n", error);
+ 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();
}
--
1.7.9.5


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