[pvrusb2] New driver snapshot: pvrusb2-mci-20080210

[Mike Isely]

On Sun, 9 Mar 2008, Mark Goldberg wrote:

> On Sun, Mar 9, 2008 at 11:57 AM, Mike Isely <isely at isely.net> wrote:
> >  As for being able to trace the cx25840 module, there are some hackish
> >  things we can do in the pvrusb2 driver to snoop the I2C traffic between
> >  the cx25840 module and the part it is controlling.  I've had to do that
> >  in the past in order to debug other problems (usually with stuck
> >  hardware).  But a more fruitful strategy might be to turn on debugging
> >  within the cx2540 module itself.  All these modules generally have a
> >  "debug" parameter you can set.  Depending on the module, that will help
> >  show what is going on.  However I have to warn you that for the sort of
> >  thing you are looking for, you will likely want to have the chip's
> >  datasheet in front of you when you do this, and this is not a simple
> >  part :-( The PDF I have for it is 289 pages.
> >
> >  Does this help with understanding things or have I muddied it up?
> 
> I'm actually a hardware engineer and have messed with the saa7134 module to add
> more controls to set additional registers so I could try to improve the capture.

Oh, then you're the ideal person to chase this :-)  Need the datasheet?


> 
> Besides, you can't let the smoke out any more from your monitor if you
> send it the wrong
> sync signals. I assume you can't physically break the pvrusb2 by
> sending wrong stuff to
> the registers.

Well *I've* never busted a pvrusb2 by sending it bad data.  And I have 
sent it my share of truly bad data.  And I've yanked it while running, 
forced it to crash, etc, etc.  So you're probably fine.


> 
> I can tell you that from /var/log/messages, it gets intitialized
> differently. The newer module has:
> 
> Feb 11 06:08:01 localhost kernel: cx25840 3-0044: Specified standard:
>      automatic detection
> Feb 11 06:08:01 localhost kernel: cx25840 3-0044: Specified audioclock
> freq: 44100 Hz
> 
> while the older one that works correctly has:
> 
> Feb 11 06:26:44 localhost kernel: cx25840 4-0044: Specified standard:
>      NTSC-M
> Feb 11 06:26:44 localhost kernel: cx25840 4-0044: Specified audioclock
> freq: 48000 Hz
> 
> I'll turn on debug for the xcx25840 and see what I can see.
> 

Then it sounds like you have some bug chasing to do.  Good luck :-)

Note: I'm not the maintainer of that module and I'm hardly an expert on 
it.  But at least one other person on this list knows quite a bit about 
its internals.  If you find something and he doesn't speak up first, 
I'll do what I can to help you get any fixes applied...

  -Mike

-- 

Mike Isely
isely @ pobox (dot) com
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