[linux-dvb] Re: [PATCH] fix for stream corruption on budget /Nova-T cards

[Jon Burgess <mplayer@jburgess.uklinux.net>]

Robert Schlabbach wrote:

> The hardware does not generate any VSYNC signals, and thus no frame
> signals. To utilize the odd/even field DMA mechanism, you have to program
> the SAA7146A to force the toggling of the field. See the DD1_INIT register
> settings for details.
OK, I was under the impression from this posting earlier from Emard that 
some boards did have some hardware to generate this fake vsync:

  "The source or the problem was blamed on separate vsync detection
  chip found mostly on budget cards. This chip and 7146 can have
  slightly different timing of vsync and therefrom came the DMA blocks
  missing in the previous code. "

Also this comment is from the budget-patch code:

**      Currently, the TT_budget / WinTV_Nova cards have two ICs
**      (74HCT4040, LVC74) for the generation of this VSYNC signal,
**      which seems that can be done perfectly without this :-)).

These chips are on my budget board but still I see no vsync's (unless 
they need the config of the register you mention).

I was wondering whether some boards did have a vsync being generated 
which probably needs some special handling when reading the DMA buffer.
This might be why some people seem to be reporting that my recent change 
to this code has broken their setup.

	Jon




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