From: Guenter Roeck <linux@roeck-us.net>
To: "Heiko Stübner" <heiko@sntech.de>,
"Ulf Hansson" <ulf.hansson@linaro.org>,
"Alexandre Courbot" <acourbot@nvidia.com>,
"Marek Szyprowski" <m.szyprowski@samsung.com>
Cc: linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: Usage of restart_handler in pwrseq_emmc
Date: Tue, 02 Jun 2015 09:42:39 -0700 [thread overview]
Message-ID: <556DDCFF.8000200@roeck-us.net> (raw)
In-Reply-To: <1789396.sexGZzDeEb@diego>
On 06/02/2015 08:29 AM, Heiko Stübner wrote:
> Hi,
>
> I'm confused by the pwrseq-emmc registering a restart_handler for resetting an
> emmc in a panic-reboot case at priority 129 to "schedules it just before
> system reboot".
>
>>From what I remember from the restart-handler discussion the actuall usage is
> traversing the ordered list until one registered handler sucessfully restarts
> the system and not to have arbitary actions in there not related to the actual
> restart process?
>
> The actual documentation in kernel/reboot.c supports this assumption,
> describing register_restart_handler as "Register function to be called to
> reset the system".
>
>
> Additionally, 128 isn't even _the_ priority to reboot the system as described
> above and some drivers use higher priorities per default, see in
> drivers/power/reset arm-versatile-reboot.c; at91-reset.c; rmobile-reset.c and
> some more.
>
>
> So I guess this should use some other mechanism (reboot notifier) instead of
> restart_handlers?
>
Looks like it. Assuming that a restart handler with priority 129 will always
be executed is a bad idea, and having it do anything but restart the system
is an even worse idea and is really asking for trouble.
Guenter
next prev parent reply other threads:[~2015-06-02 16:42 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-02 15:29 Usage of restart_handler in pwrseq_emmc Heiko Stübner
2015-06-02 16:42 ` Guenter Roeck [this message]
2015-06-03 10:01 ` Marek Szyprowski
2015-06-03 15:03 ` Guenter Roeck
2015-06-08 9:36 ` Marek Szyprowski
2015-06-08 15:00 ` Guenter Roeck
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