How to force the device assignment with V4l V2.0?

I have two devices - a CX88 based Hauppauge TV PCI card, and a USB webcam. In the "old" style drivers, I could force the loading of the two modules (cx8800 and gspca) in a set sequence, using blacklist and modules.autoload. This is enough to ensure that cx88 gets /dev/video0, and the usb webcam gets /dev/video1.

Quoted 5 lines · Ian Pickworth

I have two devices - a CX88 based Hauppauge TV PCI card, and a USB webcam. In the "old" style drivers, I could force the loading of the two modules (cx8800 and gspca) in a set sequence, using blacklist and modules.autoload. This is enough to ensure that cx88 gets /dev/video0, and the usb webcam gets /dev/video1.

I use udev rules to give persistent names.

Here is my /etc/udev/rules.d/video.rules file, which creates /dev/webcam and /dev/tvtuner as appropriate.

KERNEL=="video*" SYSFS{name}=="USB2.0 Camera", NAME="video%n", SYMLINK+="webcam" KERNEL=="video*" SYSFS{name}=="em28xx*", NAME="video%n", SYMLINK+="tvtuner"

To find distinguishing attributes to match on use:

echo /sys/class/video4linux/video* | xargs -n1 udevinfo -a -p

Quoted 16 lines · Pádraig Brady

Quoted 6 lines · Ian Pickworth

I have two devices - a CX88 based Hauppauge TV PCI card, and a USB webcam. In the "old" style drivers, I could force the loading of the two modules (cx8800 and gspca) in a set sequence, using blacklist and modules.autoload. This is enough to ensure that cx88 gets /dev/video0, and the usb webcam gets /dev/video1.

I use udev rules to give persistent names.

Here is my /etc/udev/rules.d/video.rules file, which creates /dev/webcam and /dev/tvtuner as appropriate.

KERNEL=="video*" SYSFS{name}=="USB2.0 Camera", NAME="video%n", SYMLINK+="webcam" KERNEL=="video*" SYSFS{name}=="em28xx*", NAME="video%n", SYMLINK+="tvtuner"

Quoted 4 lines

To find distinguishing attributes to match on use:

echo /sys/class/video4linux/video* | xargs -n1 udevinfo -a -p

I did think about that, but the problem is that applications want to see /dev/video(n) style names. Especially TV Time that (I think) uses /dev/video - set to link to /dev/video0 by the standard udev rules.

I'm having a play with the latest code from hg on the 2.6.27 kernel, Gentoo installation. This is triggered by the gspca driver being absorbed into the main tree (which is a great move by the way).

I have two devices - a CX88 based Hauppauge TV PCI card, and a USB webcam. In the "old" style drivers, I could force the loading of the two modules (cx8800 and gspca) in a set sequence, using blacklist and modules.autoload. This is enough to ensure that cx88 gets /dev/video0, and the usb webcam gets /dev/video1.

However, when trying a recent hg snapshot, the sequence of loading the modules does not change what the V4l driver is doing when loaded. Looking at dmesg, I see that the new drivers are doing quite a lot of detecting work themselves - it looks like they pick up the USB device first regardless of the module blacklist/load sequence I have specified.

So, question is: Is there a preferred way of forcing the sequence of device assignment in V4L these days? I need the cx88 to be /dev/video0 and the USB webcam to be /dev/video1 - otherwise all sorts of programs get confused.