[pvrusb2] in-kernel driver & corrupt video

[Mike Isely]

On Thu, 28 Sep 2006, Rick Immel wrote:

> pvrusb2 at isely.net wrote:
> > I just got my Slackware distro installed with the 2.6.18.kernel.  I 
> > copied the three driver extract files to the /lib/firmware directory 
> > for my 24xxx hardware.  I plugged the hardware in and it worked, sort 
> > of.  The sound  is good, but the video is corrupted  when using xine 
> > or mplayer.   I haven't installed MythTV yet, but there appears to be 
> > a problem with the in-kernel driver.  I tested my hardware on another 
> > machine running a 2.6.17 kernel, the same firmware, and the standalone 
> > driver (20060903).  This configuration presents good audio and video 
> > with xine and mplayer.  Has someone else experienced this problem?
> >
> > Can you describe the nature of the corruption?  Is it periodic or random?  
> > Is the video breaking up or are you seeing uniform distortion (e.g. colors 
> > out of whack)?
> >
> > Starting with 2.6.18, commands to the mpeg2 encoder are determined by a 
> > new kernel module, cx2341x.ko.  That should be the only substantial 
> > difference.
> >
> > Can you try the standalone driver in your 2.6.18 and see if the situation 
> > is any different?  I suspect it will be the same, but if it isn't then 
> > that's another clue.  To try the standalone driver just build it as you 
> > always would and simply rename the kernel-built pvrusb2.ko out of the way.
> >
> >   -Mike
> >
> I compiled and installed the standalone driver (20060924).  This solved 
> the problem!

Hmmm.

> 
> The corruption was uniform with colors out of whack and thin blue 
> horizontal lines in the video.

Ah ha!

You're using a 24xxx device.  I'll bet your horizontal capture resolution 
is something other than 720.  Can you tell me what your capture resolution 
is?  There's a problem with 24xxx devices where if the horizontal capture 
resolution is not exactly 720 then the video is corrupted.  The key here 
is that the standalone driver has a fix that forces that value to 720 if 
you're on a 24xxx device.  This fix did not get into the in-kernel 2.6.18 
driver (I just checked it to be sure), thus when you went to the 
standalone driver the problem went away.  This fix should probably go into 
2.6.18.y...

> 
> This implies that the in-kernel driver has some problem.  Maybe its 
> specific to my Slackware distro?
> If there is anything more I can send you to help solve this problem, 
> please let me know.

Can you check what capture resolution you are/were using with the 
in-kernel driver?  It's possible to read this back via the sysfs interface 
(look at the web page documentation about sysfs for details).

  -Mike

-- 
                        |         Mike Isely          |     PGP fingerprint
     Spammers Die!!     |                             | 03 54 43 4D 75 E5 CC 92
                        |   isely @ pobox (dot) com   | 71 16 01 E2 B5 F5 C1 E8
                        |                             |