diff mbox series

[watchdog,v2] watchdog: mei_wdt: request stop on unregister

Message ID 20210124114938.373885-1-tomas.winkler@intel.com (mailing list archive)
State Accepted
Headers show
Series [watchdog,v2] watchdog: mei_wdt: request stop on unregister | expand

Commit Message

Winkler, Tomas Jan. 24, 2021, 11:49 a.m. UTC
From: Alexander Usyskin <alexander.usyskin@intel.com>

The MEI bus has a special behavior on suspend it destroys
all the attached devices, this is due to the fact that also
firmware context is not persistent across power flows.

If watchdog on MEI bus is ticking before suspending the firmware
times out and reports that the OS is missing watchdog tick.
Send the stop command to the firmware on watchdog unregistered
to eliminate the false event on suspend.
This does not make the things worse from the user-space perspective
as a user-space should re-open watchdog device after
suspending before this patch.

Cc: <stable@vger.kernel.org>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
---
V2: Update the commit message with better explanation

 drivers/watchdog/mei_wdt.c | 1 +
 1 file changed, 1 insertion(+)

Comments

Guenter Roeck Jan. 24, 2021, 3:43 p.m. UTC | #1
On Sun, Jan 24, 2021 at 01:49:38PM +0200, Tomas Winkler wrote:
> From: Alexander Usyskin <alexander.usyskin@intel.com>
> 
> The MEI bus has a special behavior on suspend it destroys
> all the attached devices, this is due to the fact that also
> firmware context is not persistent across power flows.
> 
> If watchdog on MEI bus is ticking before suspending the firmware
> times out and reports that the OS is missing watchdog tick.
> Send the stop command to the firmware on watchdog unregistered
> to eliminate the false event on suspend.
> This does not make the things worse from the user-space perspective
> as a user-space should re-open watchdog device after
> suspending before this patch.
> 
> 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>

> ---
> V2: Update the commit message with better explanation
> 
>  drivers/watchdog/mei_wdt.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/watchdog/mei_wdt.c b/drivers/watchdog/mei_wdt.c
> index 5391bf3e6b11..c5967d8b4256 100644
> --- a/drivers/watchdog/mei_wdt.c
> +++ b/drivers/watchdog/mei_wdt.c
> @@ -382,6 +382,7 @@ static int mei_wdt_register(struct mei_wdt *wdt)
>  
>  	watchdog_set_drvdata(&wdt->wdd, wdt);
>  	watchdog_stop_on_reboot(&wdt->wdd);
> +	watchdog_stop_on_unregister(&wdt->wdd);
>  
>  	ret = watchdog_register_device(&wdt->wdd);
>  	if (ret)
> -- 
> 2.26.2
>
diff mbox series

Patch

diff --git a/drivers/watchdog/mei_wdt.c b/drivers/watchdog/mei_wdt.c
index 5391bf3e6b11..c5967d8b4256 100644
--- a/drivers/watchdog/mei_wdt.c
+++ b/drivers/watchdog/mei_wdt.c
@@ -382,6 +382,7 @@  static int mei_wdt_register(struct mei_wdt *wdt)
 
 	watchdog_set_drvdata(&wdt->wdd, wdt);
 	watchdog_stop_on_reboot(&wdt->wdd);
+	watchdog_stop_on_unregister(&wdt->wdd);
 
 	ret = watchdog_register_device(&wdt->wdd);
 	if (ret)