[mythtv-users] Understanding /dev/videoN requirements

Kirk Anderson kirk at nosredna.net
Fri Feb 10 12:32:59 UTC 2006


I have an HD-3000 and PVR-350 card that have been running together fine 
for many months.
Recently I attemted to add a USB webcam onto my Myth box. All hell broke 
loose. I spent
several days playing with udev rules trying to massage these three 
/dev/videoN devices back
to their pre-webcam configuration.  But I could never get Myth to work 
as long as that webcam
was in the system.

Wondering if anyone else has similar experiences.

Here's what was there pre-webcam:
    /dev/video0  --> HD-3000
    /dev/video1  --> HD-3000
    /dev/video3  --> PVR-350

"mythtv-setup" successfully detects these video devices and is happy to 
configure them properly.

Now, I add in the webcam.  By default (without modifying udev), the 
webcam gets assigned as /dev/video1.
This apparently steals the device from the HD-3000 and also somehow 
breaks the PVR-350.

So then I got the idea to modify the udev rules files tomove the webcam 
to /dev/webcam0. This works ok.
But even when I force (through udev rules) the HD-3000 and PVR-350 to be 
back to their original /dev/video
positions,  "mythtv-setup" doesn't seem to recognize them as legitimate 
devices.  The PVR-350 menu
in mythtv-setup never sees the PVR-350.

Once I removed the webcam and undid my changes to the udev rules, 
everything works fine again.

Is there some sort of trickery going on under the covers of mythtv-setup 
with regards to the /dev/videoN
naming conventions and attaching to devices ?

Thanks for any comments
Kirk



More information about the mythtv-users mailing list