[ivtv-users] PVR-350 decoder firmware problem

[Andy Walls]

On Wed, 2009-05-20 at 09:54 -0500, Scott Reynolds wrote:
> On Sun, May 17, 2009 at 7:10 PM, Andy Walls <awalls at radix.net> wrote:
> >
> > Here are some hints on looking for possible problem changes:
> > [...]
> >
> > I'm just guessing it's a change in one of those files.  That filespec
> > limits things to 16 changesets.  If you can narrow down the date range,
> > then you can open up the log serach to all the files.
> 
> Thanks, Andy, this was well more than enough to get me going in the
> right direction. I quickly narrowed down the date to March 30, for
> which there were only two changesets for the files you indicated. I
> quickly inferred that it was this change that broke PVR-350 output on
> kernel 2.6.23:
> 
> http://linuxtv.org/hg/v4l-dvb/rev/e66ace4b4a61
> v4l2: use old-style i2c API for kernels < 2.6.26 instead of < 2.6.22
> 
> Updating to the tip and reverting this changeset (ignoring one
> harmless reject) got PVR-350 output working again for me.
> 
> Now, I'm not saying that this is the correct solution.

One could argue that if it works for you with no ill effects, then it is
a correct solution for you.


>  I defer to
> those with a much better idea of what the general effects of this
> might be. It could be that my kernel doesn't have the old-style i2c
> API compiled in, perhaps, which is why it failed in the first place.

I don't have any old kernels lying around to troubleshoot this one.
Hans would understand the implications best.

Generally though, the line of thought on the linux-media mailing list is
to provide backward compatability when reasonable, but not to work too
hard on solving backward comptability problems.  Volunteer time is
scarce.



> I'm just guessing and unfortunately my zero megabits-per-second
> Internet upgrade of late prevents me from checking right now. (The
> "upgrade" is a joke, in case it's not obvious. I expect the problem to
> be resolved by this evening, though.)
> 
> > I'm pretty happy with the AFE and VBI changes in the cx18 driver.  If
> > you have and HVR-1600 or Compro H900 or some other cx18 supported board,
> > you can test them if you like.
> 
> Let me be clear -- I record analog signals from a pair of DTV tuners
> on a PVR-150 and an HVR-1600. Playback goes through a PVR-350
> connected via S-video to the television. Now, the PVR-150 has been
> giving me stable captions (via sliced VBI) for some time now; and as
> of March 29, the cx18 driver was mostly working, with some sync issues
> and occasionally dropped captions. My goal, obviously, is to see that
> last part working.

It's likely the application side buffer handling performance problem I
fixed with the series of patches around April 15:

http://linuxtv.org/hg/v4l-dvb/shortlog/518bb17e199b


> > The PVR-350 uses a different video decoder from the CX25843, so the
> > changes in the cx18 driver won't be applicable to making VBI on a
> > PVR-350 better.
> 
> I don't mean to be contrary, but the PVR-350 is working -and- I have
> appear to have stable captions on playback for recordings from both
> the PVR-150 and the HVR-1600. Do you have any explanation?

Hmm.  Maybe I was thinking about something else.

So if everything is working for you, have fun.


> Thanks again for your help!

You're welcome.

Regards,
Andy

> Best regards,
> 
> --scott