[Buildroot] editing device_table_dev.txt

[Arnout Vandecappelle <arnout@mind.be>]

On 22/02/13 00:07, Stefan Fr?berg wrote:
> 22.2.2013 0:57, Arnout Vandecappelle kirjoitti:
>> On 21/02/13 11:32, Stefan Fr?berg wrote:
>>>>>>>>> Also kernel .config file should also have CONFIG_DEVTMPFS and
>>>>>> DEVTMPFS
>>>>>>>>> as 'y'.
>>>>>>> Sorry, that should have been CONFIG_DEVTMPFS=y and
>>>>> CONFIG_DEVTMPFS_MOUNT=y
>>>>> Kernel version 2.6.30 is too old for that.
>>>>>
>>>>> baruch
>>>>>
>>> It is ?
>>> Damn, then the only options are mdev and udev.
>>
>>   I'm afraid that mdev and udev no longer work with old kernels that
>> don't support the DEVTMPFS option...
>>
>>   mdev and udev don't create device nodes; they only do something
>> configurable when a hotplug event happens.
>>
>
> What you mean that mdev or udev does not create device nodes ???
> If older kernels don't support devtmpfs like Baruch
> said then who does that device node creation if not the mdev or udev
> when event happens ???

  Well, nobody...

  Turns out that mdev still does device node creation. Makes me wonder if 
I'm not mistaken about udev as well... I just remember hearing that 
device node creation was removed when DEVTMPFS was introduced.


>>   That said, you can create custom mdev/udev rules to create device
>> nodes. But it's all manual - and much simpler to just create the
>> device nodes manually.
>>
>
> for mdev it's just a single file, /etc/mdev.conf (I can even copy-paste
> it here, it's not that long and will cover 99% of needs).

  Yes, but that file just specifies the chmod/chown rules, not how to 
create the device nodes. But as I just saw in the code, mdev does in fact 
create the device nodes.


  Regards,
  Arnout

> for udev it punch of rules found under /lib/udev/rules.d and yes, it can
> get really tedious to play games with those files if some device node is
> not created or
> is not created with right permissions or whatever.

[snip]


-- 
Arnout Vandecappelle                          arnout at mind be
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