[PATCH] PM / core: Fix direct_complete handling for devices with no callbacks

From: Rafael J. Wysocki
Date: Tue May 22 2018 - 06:08:43 EST


From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>

Commit 08810a4119aa (PM / core: Add NEVER_SKIP and SMART_PREPARE
driver flags) inadvertently prevented the power.direct_complete flag
from being set for devices without PM callbacks and with disabled
runtime PM which also prevents power.direct_complete from being set
for their parents. That led to problems including a resume crash on
HP ZBook 14u.

Restore the previous behavior by causing power.direct_complete to be
set for those devices again, but do that in a more direct way to
avoid overlooking that case in the future.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=199693
Fixes: 08810a4119aa (PM / core: Add NEVER_SKIP and SMART_PREPARE driver flags)
Reported-by: Thomas Martitz <kugel@xxxxxxxxxxx>
Tested-by: Thomas Martitz <kugel@xxxxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
---
drivers/base/power/main.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)

Index: linux-pm/drivers/base/power/main.c
===================================================================
--- linux-pm.orig/drivers/base/power/main.c
+++ linux-pm/drivers/base/power/main.c
@@ -1920,10 +1920,8 @@ static int device_prepare(struct device

dev->power.wakeup_path = false;

- if (dev->power.no_pm_callbacks) {
- ret = 1; /* Let device go direct_complete */
+ if (dev->power.no_pm_callbacks)
goto unlock;
- }

if (dev->pm_domain)
callback = dev->pm_domain->ops.prepare;
@@ -1957,7 +1955,8 @@ unlock:
*/
spin_lock_irq(&dev->power.lock);
dev->power.direct_complete = state.event == PM_EVENT_SUSPEND &&
- pm_runtime_suspended(dev) && ret > 0 &&
+ ((pm_runtime_suspended(dev) && ret > 0) ||
+ dev->power.no_pm_callbacks) &&
!dev_pm_test_driver_flags(dev, DPM_FLAG_NEVER_SKIP);
spin_unlock_irq(&dev->power.lock);
return 0;