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From: Wolfram Sang <wsa@the-dreams.de>
To: Guenter Roeck <linux@roeck-us.net>
Cc: linux-watchdog@vger.kernel.org,
	linux-renesas-soc@vger.kernel.org,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	Wolfram Sang <wsa+renesas@sang-engineering.com>
Subject: Re: [PATCH] watchdog: renesas_wdt: support handover from bootloader
Date: Mon, 19 Aug 2019 18:06:30 +0200	[thread overview]
Message-ID: <20190819160630.GA7590@kunai> (raw)
In-Reply-To: <7d1611dd-4f9f-6385-8454-22edf778d6e5@roeck-us.net>

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> If the HW watchdog is running, the start function should not be called
> on open. It would be called after the watchdog was stopped and is then
> started again. With that, opening the watchdog the first time would not
> call this function, and started_by_fw would remain true. Closing it would
> then stopp the watchdog and call pm_runtime_put(). The next open() would
> hit the above case, and not call pm_runtime_get_sync(). pm would then be
> out of sync.
> 
> What am I missing ?

Obviously, I was missing something. I didn't see that the watchdog core
calls ->ping instead of ->start when WDOG_HW_RUNNING is set. And once
I knew about it, I even found it in the documentation:

+  Note: when you register the watchdog timer device with this bit set,
+  then opening /dev/watchdog will skip the start operation but send a keepalive
+  request instead.

This makes all my code to keep the refcnt balanced very moot.

Sorry for the noise. I will fix up things and retest.


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      reply	other threads:[~2019-08-19 16:06 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-18 18:00 [PATCH] watchdog: renesas_wdt: support handover from bootloader Wolfram Sang
2019-08-18 19:00 ` Guenter Roeck
2019-08-19 16:06   ` Wolfram Sang [this message]

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