[mythtv-users] controlling order of tuner card detection?

Brian Guilfoos mythtv at guilfoos.com
Mon Mar 5 19:39:44 UTC 2007


Rod Smith wrote:
> On Sunday 04 March 2007 14:19, Michael Thome wrote:
>> Is there any way to force detection to proceed in bus-order, presumably
>> not changing unless I swap cards?
>
> 2) Muck with your udev configuration (assuming you're using udev).

udev can be difficult to grasp - it's tremendous flexibility is both
it's greatest strength and greatest weakness, IMO.  There are a billion
ways to solve any given problem, which sucks when you are a newb just
looking for a solution, like I was.

Personally, I created "11-video.rules" in /etc/udev/rules.d, containing
this:

SUBSYSTEM=="video4linux", SYSFS{name}=="ivtv0 encoder MPEG",
SYMLINK+="sdtv0"
SUBSYSTEM=="video4linux", SYSFS{name}=="ivtv0 encoder PCM audio",
SYMLINK+="sdtv
0_audio"
SUBSYSTEM=="video4linux", SYSFS{name}=="ivtv1 encoder MPEG",
SYMLINK+="sdtv1"
SUBSYSTEM=="video4linux", SYSFS{name}=="ivtv1 encoder PCM audio",
SYMLINK+="sdtv
1_audio"

DRIVER=="saa7134", SYSFS{dev}=="81:0", SYMLINK+="hdtv0"
DRIVER=="saa7134", SYSFS{dev}=="81:1", SYMLINK+="hdtv1"

Two different approaches to identifying the two tuner types, but it
works great.  You should probably always choose to symlink to the
original /dev/video? devices, to avoid breaking anything.  In my case,
my two HDTV tuners are /dev/hdtv0 and /dev/hdtv1, and the two tuners on
the PVR-500 are /dev/sdtv0 and /dev/sdtv1.

Good luck.  You will likely be spending some time poking around in
/sys/video4linux figuring out unique values for your cards.


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