linux-kernel - Re: loading ipmi_watchdog causes tons of other watchdog modules to be loaded

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Message-ID: <ac3eb2510810091209rd76c8a4j83a6a48d5db5d4f9@mail.gmail.com>
Date:	Thu, 9 Oct 2008 21:09:26 +0200
From:	"Kay Sievers" <kay.sievers@...y.org>
To:	"Arkadiusz Miskiewicz" <a.miskiewicz@...il.com>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: loading ipmi_watchdog causes tons of other watchdog modules to be loaded

On Thu, Oct 9, 2008 at 9:02 PM, Arkadiusz Miskiewicz
<a.miskiewicz@...il.com> wrote:
> On Thursday 09 October 2008, Kay Sievers wrote:
>> On Thu, Oct 9, 2008 at 7:22 PM, Arkadiusz Miskiewicz
>>
>
>> > ... but that ipmi_watchdog is the correct driver that handles
>> > /dev/watchdog, so this shouldn't be happening, correct?
>>
>> While the driver you expect to work is loaded, what does:
>>   ls -l /dev/watchdog
>> print?
>>
>> If the devno of this node is 10:130, what does:
>>   find /sys/class /sys/devices/ -name dev | xargs grep 10:130
>> print?
>
> # ls -l /dev/watchdog
> crw------- 1 root root 10, 130 sie  8 17:00 /dev/watchdog
> # find /sys/class /sys/devices/ -name dev | xargs grep 10:130
> /sys/class/misc/watchdog/dev:10:130

Ok, so you actually have a driver bound to that device number, and it
should not trigger the usual module autoloading mechanism.

What does:
  ls -l /sys/class/misc/watchdog/
and
  ls -l /sys/class/misc/watchdog/device/
print?

Does the /sys/class/misc/watchdog/ directory exist, before you load
the module you expect to be the driver behind /dev/watchdog?

To clarify, the other modules get loaded, after you loaded but module,
the above /sys/class/misc/watchdog/ directory exists, and only if you
read from the device, all the other modules get loaded?

Kay
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