[linux-dvb] patch "budget-av: Remove polarity switching of the clock for the DVB-C cards" causes corrupt stream

e9hack e9hack at googlemail.com
Sun Apr 29 15:41:48 CEST 2007


Matthias Dahl wrote:
> Hi.
> 
> A few days ago I upgraded to 2.6.21-rc7-git8 and along that way also to a 
> recent checkout of the v4l-dvb hg tree. After that most of the DVB-C streams 
> I receive are corrupt. (lot of a/v artefacts)
> 
> After some digging around, I was able to spot the above mentioned patch as the 
> culprit. Everything works fine till hg r5541, starting with r5542 the streams 
> get corrupted.
> 
> I have a KNC One DVB-C Plus with a Cineview module connected, running with 
> budget_av and budget_ci:

Maybe, you are the first one, who uses the driver with a DVB-C card and with a CAM. Can you remove the Cineview module
from the card and check if you get the same problems with FTA channels?

> What's strange, even though I pass bufsize=1410 to budget_core, the buffer 
> size is somewhat lower with >r5541 than with <=r5541.
> 

The transfer mode of the saa7146 was changed. The max buffer size is now 1316kB instead of 1410kB. For larger buffers,
the saa7146 uses the odd/even buffer mode. Can you test the driver with a lower buffer size (max 658kB)? In this case,
the saa7146 uses the single buffer mode. If this doesn't help, can you revert only budget-core.c to r5541 and try it
again? In the old version the saa7146 uses a line size of two TS packets (376 byte). In the new version the line size is
reduced to one TS packet (188 byte). If you can test your card on windows. I'm interested on the output of the
saa7146dump utility (http://www.linuxtv.org/downloads/saa7146dump-0.2.zip).

- Hartmut



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