From: Andrew Gaylard <ag@ffroot.co.za>
To: Guenter Roeck <linux@roeck-us.net>
Cc: linux-watchdog@vger.kernel.org, xt.hu@cqplus1.com,
wim@linux-watchdog.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] watchdog: sunplus: fix sp_wdt_restart spin loop and timeout
Date: Thu, 20 Aug 2026 17:12:11 +0200 [thread overview]
Message-ID: <sa6wltkx1v8.fsf@dev-ag> (raw)
In-Reply-To: <d37eef21-a877-4500-a280-493e98c68701@roeck-us.net> (Guenter Roeck's message of "Thu, 20 Aug 2026 06:42:30 -0700")
Guenter Roeck <linux@roeck-us.net> writes:
> On Thu, Aug 20, 2026 at 02:53:04PM +0200, Andrew Gaylard wrote:
>> sp_wdt_restart() returns immediately after writing WDT_RESUME. The
>> kernel continues executing and the watchdog kthread could pet the
>> watchdog before the short timeout expired, preventing reset.
>
> Is this observed behavior or just an assumption ?
It's an assumption.
>> Add a spin loop so no other CPU can pet the watchdog while waiting for
>> the reset. Set the restart timeout to ~1.5s.
>
> I understand the first part, but why delay the reset by 1.5s ?
> That is a functional change which needs an explanation.
I had a printf there to confirm that it actually reached that point,
so I needed the delay.
--
Andrew
next prev parent reply other threads:[~2026-08-20 15:12 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-20 12:53 [PATCH] watchdog: sunplus: fix sp_wdt_restart spin loop and timeout Andrew Gaylard
2026-08-20 13:06 ` sashiko-bot
2026-08-20 13:42 ` Guenter Roeck
2026-08-20 15:12 ` Andrew Gaylard [this message]
2026-08-20 16:05 ` Guenter Roeck
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