[watchdog] watchdog: mei_wdt: request stop on reboot to prevent false positive event

[watchdog] watchdog: mei_wdt: request stop on reboot to prevent false positive event

[Tomas Winkler]

From: Alexander Usyskin <alexander.usyskin@intel.com>

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.

Cc: <stable@vger.kernel.org>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
---
 drivers/watchdog/mei_wdt.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/watchdog/mei_wdt.c b/drivers/watchdog/mei_wdt.c
index e0af52265511..40953fe4db86 100644
--- a/drivers/watchdog/mei_wdt.c
+++ b/drivers/watchdog/mei_wdt.c
@@ -389,6 +389,8 @@ static int mei_wdt_register(struct mei_wdt *wdt)
 	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);
-- 
2.7.4

Re: [watchdog] watchdog: mei_wdt: request stop on reboot to prevent false positive event

[Guenter Roeck]

On 11/08/2016 07:55 AM, Tomas Winkler wrote:
> From: Alexander Usyskin <alexander.usyskin@intel.com>
>
> 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.
>
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
> Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

> ---
>  drivers/watchdog/mei_wdt.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/drivers/watchdog/mei_wdt.c b/drivers/watchdog/mei_wdt.c
> index e0af52265511..40953fe4db86 100644
> --- a/drivers/watchdog/mei_wdt.c
> +++ b/drivers/watchdog/mei_wdt.c
> @@ -389,6 +389,8 @@ static int mei_wdt_register(struct mei_wdt *wdt)
>  	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);
>