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

From: Nitish Ambastha
Date: Mon Jun 29 2015 - 03:01:39 EST


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@xxxxxxxxxxx>
---
kernel/power/autosleep.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/kernel/power/autosleep.c b/kernel/power/autosleep.c
index 9012ecf..3923148 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;
@@ -45,10 +46,20 @@ static void try_to_suspend(struct work_struct *work)
if (autosleep_state >= PM_SUSPEND_MAX)
hibernate();
else
- pm_suspend(autosleep_state);
+ error = pm_suspend(autosleep_state);

mutex_unlock(&autosleep_lock);

+ if (error) {
+ /*
+ * If some devices failed to suspend, its better to wait
+ * to prevent system from trying to suspend in tight loop
+ */
+ pr_info("PM: suspend returned (%d)\n", error);
+ schedule_timeout_uninterruptible(HZ / 2);
+ goto out;
+ }
+
if (!pm_get_wakeup_count(&final_count, false))
goto out;

--
1.7.9.5

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