[Buildroot] [PATCH] linux: don't automatically set uevent_helper with mdev /dev management
Peter Korsgaard
jacmet at uclibc.org
Fri Feb 7 21:05:19 UTC 2014
>>>>> "Thomas" == Thomas De Schampheleire <patrickdepinguin at gmail.com> writes:
Hi,
>> Hmm, but the the coldplug handling with 'mdev -s' afaik doesn't handle
>> module or firmware loading, so those features will break from this.
> Isn't this handled by the installation of the hotplug helper from
> S10mdev, after which mdev -s is run?
Yes, if the events happen after that line, but not if they happen
before.
> I.e. everything that happened before S10mdev is caught by 'mdev -s'
> and everything after is handled by the hotplug helper, right?
No, mdev -s only scans /sys for devices and create the corresponding
device nodes (already done by devtmpfs) and execute whatever commands
you have defined, it afaik doesn't handle module load or firmware requests.
>> I would be interested in knowing why hotplug is so much slower than
>> coldplug. Do you have any idea about how many times mdev gets executed
>> during bootup?
>>
> No, I don't know. I do know that on one particular arm-based single
> core system, the time to enter userspace increased from 2 seconds to
> 10 seconds due to this hotplug helper.
Funky. I personally have never used mdev, but that sounds pretty
extreme.
--
Bye, Peter Korsgaard
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