Make /dev/video* Static

[Freddie]

I have a PVR-150 and a Nova-T. Both of those export something to /dev/video. However, I am only interested in the PVR-150. Problem is that this changes seemingly random at boot-up.

How can I fix this?

Regards, Freddie.

[KillerKiwi]

You need to create a udev rule, this will make a symlink that is always pointed to the correct device

You can use the attahed script to do it for you

syntax

sudo python udev-rules.py CURRENT_DEV SYMLINK

or

sudo python udev-rules.py /dev/video0 /dev/video_pvr150
sudo python udev-rules.py /dev/video1 /dev/video_novaT

[Freddie]

Originally Posted by KillerKiwi You need to create a udev rule, this will make a symlink that is always pointed to the correct device You can use the attahed script to do it for you syntax sudo python udev-rules.py CURRENT_DEV SYMLINK or sudo python udev-rules.py /dev/video0 /dev/video_pvr150 sudo python udev-rules.py /dev/video1 /dev/video_novaT

Thank you! That worked an absolute treat.

Regards, Freddie.

[mo-hog]

KillerKiwi (great to see another Kiwi around!)

I just used your script and it was exactly what I needed to fix this:
https://answers.launchpad.net/ubuntu...n/65286/+index

This is an excellent little script for this task. It would be great if you could clarify the license (add a GPLv3 header into the script, perhaps?) and post it somewhere that doesn't require a login to get to. Perhaps you could add a short page to the Ubuntu wiki and add the file there. I am happy to put it on my site if you have nowhere else. It would mean that mailing lists and "Answers" can link directly to the script and not require people (like me) to get an ubuntuforums login to solve the udev problem. At the moment, viewing ubuntuforums attachments requires a login.

Thanks again!!

[KillerKiwi]

consider it gpl2

hopefully the need for this will disappear soon...

[kees]

MythTV should be taught to use the static device names in /dev/v4l/by-path/* (which exist starting in Intrepid). That's how static naming is being solved.

[mo-hog]

I agree - MythTV should be changed to support /dev/v4l/by-paths - I've filed a bug here:
https://bugs.launchpad.net/ubuntu/+s...ta/+bug/370696

The python script did not work in Jaunty because "udevinfo" is no longer supported. I have updated the script to work with udevadm instead, which is the new way to access udevinfo.

I have also added a GPLv2 header to the file (though I don't know your name, so only put KillerKiwi!) and made it available through the launchpad bug above as well. I hope you don't mind.

[KillerKiwi]

cool, thanks for updating the script will be handy when I update

[Tim L]

This looks exactly like what I need to solve my problem – I have downloaded the python script – but do not know what to do with it – where do I put it – how do I get it to work – at what stage do I install it? Can someone point be in the right direction. Sorry to ask such basic questions.

[KillerKiwi]

ok

When your system starts it assigns all video devices (webcams, capture cards etc) to a node like below

• /dev/video0
• /dev/video1
• /dev/video2
• etc

The issue is video0, video1 and video2 may swap which device it points to on boot

Now the script can create a permanent node that ALWAYS points to the correct device.

So you run a line like below for your video devices (replace PVR150 with a name for the device)

sudo python udev-rules-jaunty.py /dev/video0 /dev/video_PVR150

You can then update myth backend to point to /dev/video_PVR150 (or what ever you called it) instead of /dev/video0

Problem solved

There is a fix to this coming, but until then...