[ale] Obtaining stable /dev names with changing probe order

Michael D. Hirsch mhirsch at nubridges.com
Thu Aug 26 09:53:57 EDT 2004


On Thursday 26 August 2004 07:34 am, Jason Day wrote:
> On Wed, Aug 25, 2004 at 05:25:51PM -0400, tfreeman at intel.digichem.net wrote:
> > On this machine I have a Hauppaugh bttv based TV/radio card (model#
> > forgotten and hopefully unimportant) which works fine as /dev/video0 if I
> > don't get cute. If I add a usb webcam (a Kensington usually) after
> > logging in, the usb device becomes /dev/video1. If, however, I reboot
> > while the usb device is still plugged in, the usb device is detected
> > first and becomes /dev/video0, leaving the TV card to become /dev/video1,
> > which disrupts the userlevel software something aweful. Does anyone on
> > this list know how to cause these devices to be found at a stable
> > /dev/video# regardless of probe order? Two days of google & reading in
> > the kernel docs has declined to enlighten me as yet.
>
> Udev is what you want, it replaces devfs.  I don't know how easy it
> would be to setup on FC2 though.
>
> There are some tips in this thread from a month back:
> http://www.ale.org/archive/ale/ale-2004-07/msg00540.html

Try installing udev (apt-get install udev, if you use apt) and follow the 
instructions in http://www.linuxjournal.com/article.php?sid=7316

udev installs the devices in /sys, so you'll have to figure out how to get 
your software to work with /sys/video0.  I suppose a symlink might work if 
you can't redirect the software through the config file.

Michael



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