[PATCH 4.9 74/83] watchdog: mei_wdt: request stop on reboot to prevent false positive event

[Greg Kroah-Hartman]

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

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

From: Alexander Usyskin <alexander.usyskin@xxxxxxxxx>

commit 9eff1140a82db8c5520f76e51c21827b4af670b3 upstream.

Systemd on reboot enables shutdown watchdog that leaves the watchdog
device open to ensure that even if power down process get stuck the
platform reboots nonetheless.
The iamt_wdt is an alarm-only watchdog and can't reboot system, but the
FW will generate an alarm event reboot was completed in time, as the
watchdog is not automatically disabled during power cycle.
So we should request stop watchdog on reboot to eliminate wrong alarm
from the FW.

Signed-off-by: Alexander Usyskin <alexander.usyskin@xxxxxxxxx>
Signed-off-by: Tomas Winkler <tomas.winkler@xxxxxxxxx>
Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/watchdog/mei_wdt.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/watchdog/mei_wdt.c
+++ b/drivers/watchdog/mei_wdt.c
@@ -389,6 +389,8 @@ static int mei_wdt_register(struct mei_w
 	wdt->wdd.max_timeout = MEI_WDT_MAX_TIMEOUT;
 
 	watchdog_set_drvdata(&wdt->wdd, wdt);
+	watchdog_stop_on_reboot(&wdt->wdd);
+
 	ret = watchdog_register_device(&wdt->wdd);
 	if (ret) {
 		dev_err(dev, "unable to register watchdog device = %d.\n", ret);