[mythtv] Mythtv and kernel 2.6.25

[Andrew M. Bishop]

"Paulo Cavalcanti" <promac at gmail.com> writes:

> On Sun, Jun 22, 2008 at 6:56 AM, Andrew M. Bishop <amb at gedanken.demon.co.uk>
> wrote:
>
>> "Paulo Cavalcanti" <promac at gmail.com> writes:
>>
>> >> > I am having problems to make mythtv work with kernel 2.6.25 (Fedora 8).
>> >> >
>> >> > The problem seems to be my capture card, a Prolink Pixelview.

>> I had the same problem and stayed on kernel 2.6.24 with my bttv cards.
>> I did some investigation and the problem seems to be related to the
>> changeover to V4L2 in 2.6.25.
>>
>> This message http://lkml.org/lkml/2008/1/6/83 describes a patch to the
>> bttv driver, but if you look at the 2.6.25 kernel source you will see
>> that it isn't there.  If you apply this patch (like I tried) then it
>> will get further, it won't lockup but I didn't get any video either.

> I rebuilt video4linux from ATrpms using today's snapshot,
> and it worked.
>
> Well, almost. If I try mythtv Live TV after rebooting, I get a green screen
> (but no lock).

This is what I got when I tried my home-made patch with the raw 2.6.25
kernel - a green screen instead of a picture.

I enabled all of the debugging that I could find and this was the
error message that I was getting:

v4l1-compat: VIDIOCMCAPTURE / VIDIOC_S_FMT: -16


To bring this back on topic for mythtv-dev: I think that the problem
is that mythtv uses partly or mostly V4L1 and with newer kernels this
is provided only by a compatibility layer.  The VIDIOCGMBUF and
VIDIOCMCAPTURE ioctls (which are the ones causing the two problems
here) are both V4L1.  If the V4L1 layer ever goes away then mythtv
will need to switch over.


> However, If I run mplayer before using mythtv, Live TV works just fine.
> Maybe this is related to the nvidia driver I am using. I did not try the
> latest one (173.14.09).
>
> I will ask Axel to make video4linux (20080622) available to the public.

Probably this configures the tuner in some way that is different from
mythtv and the settings stick.

-- 
Andrew.
----------------------------------------------------------------------
Andrew M. Bishop                             amb at gedanken.demon.co.uk
                                      http://www.gedanken.demon.co.uk/