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SubjectRe: 2.5.50 - sound driver issues with i810_audio
From Valdis.Kletnieks@vt ...
DateThu, 12 Dec 2002 00:51:08 -0500
On Wed, 11 Dec 2002 17:59:28 EST, Doug Ledford said:

> This sounds like the problem some chipsets had with wrapping counters in 
> the dma pointer read code.  Basically, when the sg segment is advanced to 
> the next segment, the offset counter would not be simultaneously cleared 
> but instead would be momentarily delayed before the clear occured and a 
> read at just the wrong time could result in us thinking that the buffer 
> was a full sg segment farther than it was.  There were changes made to the 
> oss i810 driver around version 0.18 to solve this problem if I remember 
> correctly.  Similar code may be needed in the alsa driver, I'm not sure 
> because I have looked at it or tried it (my machine with an i810 doesn't 
> run 2.5 kernels).

Ahh... That would exactly explain what I was seeing, and why it worked under
2.4.18 for me, and gives me a good idea where to look (the relevant code in the
alsa and oss drivers is pretty similar, there's only so many ways to code a
ring buffer when the other part is cast in silicon. ;)

/Valdis

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