[PATCH 3.16.y-ckt 135/170] PM / Sleep: fix async suspend_late/freeze_late error handling

[Luis Henriques]

3.16.7-ckt1 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Imre Deak <imre.deak at intel.com>

commit 246ef766743618a7cab059d6c4993270075b173e upstream.

If an asynchronous suspend_late or freeze_late callback fails
during the SUSPEND, FREEZE or QUIESCE phases, we don't propagate the
corresponding error correctly, in effect ignoring the error and
continuing the suspend-to-ram/hibernation. During suspend-to-ram this
could leave some devices without a valid saved context, leading to a
failure to reinitialize them during resume. During hibernation this
could leave some devices active interfeering with the creation /
restoration of the hibernation image. Also this could leave the
corresponding devices without a valid saved context and failure to
reinitialize them during resume.

Fixes: de377b397272 (PM / sleep: Asynchronous threads for suspend_late)
Signed-off-by: Imre Deak <imre.deak at intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki at intel.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/base/power/main.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index bf412961a934..1f6da3ad6db0 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -1262,6 +1262,8 @@ static int dpm_suspend_late(pm_message_t state)
 	}
 	mutex_unlock(&dpm_list_mtx);
 	async_synchronize_full();
+	if (!error)
+		error = async_error;
 	if (error) {
 		suspend_stats.failed_suspend_late++;
 		dpm_save_failed_step(SUSPEND_SUSPEND_LATE);
-- 
2.1.0