[PATCH] Watchdog: OMAP: Fix the runtime pm code to avoid module getting stuck intransition state.

? 2012?07?08? 17:26, Wim Van Sebroeck ??:

Hi All,

quoted

Hello, Lokesh,

One question: Does "echo 1>  /dev/watchdog" work well?

Regards,
Zumeng

Please note hat "echo 1>  /dev/watchdog" for drivers that have the WDIOF_MAGICCLOSE
flag set, reboots the system. This is because it opens the watchdog device ; then
writes the characters "1" to it and then closes the watchdog. So the watchdog keeps
running (because it didn't see the magic char "V" written to it).

Yes, this is _absolutely_ right.

In this case (omap_wdt) it opens the watchdog device (and starts the watchdog) then
it writes a "1" to the watchdog (so basically the watchdog is being pinged) and then
closes the watchdog device (which stops the watchdog if NOWAYOUT was not set).

Wim,

Agreed for all above, sorry for jumping in:

I just have a little question about this patch:


we have enable pm_runtime_enable(wdev->dev) in probe,
and do ret = misc_register(&(wdev->omap_wdt_miscdev));

Then this patch wants to remove pm_runtime_get_sync
in file operation function, is that right?

Regards,
Zumeng

Kind regards,
Wim.

On Mon, Jul 9, 2012 at 6:46 AM, Zumeng Chen [off-list ref] wrote:

? 2012?07?08? 17:26, Wim Van Sebroeck ??:

quoted

Hi All,

quoted

Hello, Lokesh,

One question: Does "echo 1>  /dev/watchdog" work well?

Regards,
Zumeng

Please note hat "echo 1>  /dev/watchdog" for drivers that have the
WDIOF_MAGICCLOSE
flag set, reboots the system. This is because it opens the watchdog device
; then
writes the characters "1" to it and then closes the watchdog. So the
watchdog keeps
running (because it didn't see the magic char "V" written to it).

Yes, this is _absolutely_ right.

quoted

In this case (omap_wdt) it opens the watchdog device (and starts the
watchdog) then
it writes a "1" to the watchdog (so basically the watchdog is being
pinged) and then
closes the watchdog device (which stops the watchdog if NOWAYOUT was not
set).

Wim,

Agreed for all above, sorry for jumping in:

I just have a little question about this patch:


we have enable pm_runtime_enable(wdev->dev) in probe,
and do ret = misc_register(&(wdev->omap_wdt_miscdev));

Then this patch wants to remove pm_runtime_get_sync
in file operation function, is that right?

Yes, this patch removes pm_runtime_get/put_sync when we
know that watchdog is running.

Regards,
Zumeng

quoted

Kind regards,
Wim.