[mythtv-users] How to make static device nodes for video capture cards in MythTV .22?

[Eloy Paris]

On Wed, Dec 09, 2009 at 10:44:26AM -0600, Kevin Kuphal wrote:

> On Wed, Dec 9, 2009 at 10:02 AM, Dave <dave at davestechshop.net> wrote:
>
> > I am running Mythbuntu 9.10 with 1 PVR150 and 1
> > HVR850. When I reboot, the PVR150 is changing device
> > nodes. I tried the script mentioned in this thread
> > (http://ubuntuforums.org/showthread.php?t=753434) and I do get a
> > symlink, but I do not see the new static device node as an option in
> > myth backend setup.
> >
> > Does this "Ubuntu Jaunty" script work in Mythbuntu 9.10 / MythTV
> > .22?
> >
> > Is there a better solution yet?
> >
> > What can I do now, other than not reboot? ;)
> 
> The hard way: write udev rules
> This has always troubled me
> 
> Easy way (for me): Add an option line to your ivtv module in modprobe.conf
> options ivtv ivtv_first_minor=1
> 
> This will cause ivtv to always take /dev/video1 (double check with a
> google search to see if ivtv_first_minor is 0 based) and should leave
> /dev/video0 for your other card

I have a PVR-500 (ivtv), an HVR-1600 (cx18), an old ATI TV Wonder LE
framegrabber (bttv), and a webcam (pwc). All of these create /dev/videoX
files and other /dev/* nodes so it's a mess to leave things up to udev
since there's always some device re-ordering.

My solution, which has worked great for me, was to add the following to
/etc/modprobe.d/blacklist.conf:

blacklist ivtv
blacklist pwc
blacklist bttv
blacklist cx18

This prevents the kernel from auto-loading in some random order the
kernel modules for my video devices.

Then, I add to /etc/modules the list of modules to load *in order*. This
way the devices are loaded in the order I want and the /dev/* nodes are
always what I want and have configured in MythTV.

Kevin's method above is another alternative, but it relies on a driver
(the ivtv driver in this case) supporting an option to specify the minor
device number, which is something that not all drivers support.

Hope this helps.

Cheers,

Eloy Paris.-