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Re: debian and UDEV

On Thu, May 18, 2006 at 07:16:00PM +0200, Goswin von Brederlow wrote:

> That is because udev is slower so the window of the race condition
> gets increased many many times. Without udev you don't have to wait
> for the mknod call to complete.

I think you got the speed comparison wrong: udev does the mknod() from a
C program running as a daemon, while hotplug means forking a new shell
for every event. That should be several magnitudes slower.

> And for most hardware that actualy makes the race condition
> disapear. Just broken stuff like usb that has asynchronous device
> detection it still breaks.

No, you're mixing things up. It seems that what you have a problem with
is the dynamic /dev. Since hotplug does not provide a dynamic /dev,
programs that assume /dev nodes are always there will of course work.
Try adding "UDEV_DISABLED=yes" to /etc/udev.conf to disable the dynamic
/dev (sorry, Marco :-)

IMHO if you build a kernel with devfs or ndevfs enabled you'll have
exactly the same races with hotplug than you have with udev.


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