[Buildroot] editing device_table_dev.txt

Peter Korsgaard jacmet at uclibc.org
Sun Feb 24 18:11:00 UTC 2013


>>>>> "Thomas" == Thomas Petazzoni <thomas.petazzoni at free-electrons.com> writes:

 >> 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.

 Thomas> Yes, I think you got the thing wrong: udev and mdev are still
 Thomas> creating the device nodes. Of course, they might have already
 Thomas> been created by devtmpfs, but I don't think it is a
 Thomas> requirement. At least, devtmpfs is definitely not a requirement
 Thomas> for mdev to work (except in Buildroot, in which we made the
 Thomas> decision that if mdev is to be used, then devtmpfs support must
 Thomas> be there).

And the main reason for this is that you need a writable /dev and basic
device nodes before mdev starts up, and the simplest way of getting this
is using devtmpfs.

What mdev/udev buys you over pure devtmpfs is the possibility of custom
rules (names/permissions/programs executed).

-- 
Bye, Peter Korsgaard



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