Re: [PATCH] Fix SAA7134 transport stream errors

[Gerd Knorr]

On Tue, Feb 01, 2005 at 08:19:17PM -0500, Eric Lammerts wrote:
> 
> Hi,
> I had a lot of problems with the transport stream input on the
> SAA7134. Even the slighest bit of other system activity caused data
> corruption. This patch corrects the switching of the two DMA
> buffers.

Thanks, merged (and fixed a simliar issue in saa7134-video.c along the
way ;).

> FYI, the problems only occur on Transmeta TM5800/TM5400 Crusoe boards
> (1GHz/533MHz). When I move the SAA7134 board to a 400MHz Celeron, no
> problems at all. I measured the interrupt latency of the SAA7134
> interrupt on the Crusoe, and that peaks to >1000us when power
> management is enabled and other activity (IDE DMA) is taking place!!
> That may explain why other people haven't seen this problem.

It has shown up before already (long ago), thats why the two-buffer
thingy exists in the first place.  Looks like 2.6 really makes a better
job on low-latency than 2.4 did, otherwise that would have been noticed
earlier...

  Gerd

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