Re: lowlatency 2.2.19

[Andrew Morton]

safemode wrote:
> 
> this is just a general question about low latency patches on 2.2,   I
> remember hearing about low latency patches for 2.4 not playing well with X
> 4.x, is this true for 2.2 low latency patches as well?

Yes, it would be the case.

Some video cards have a PCI cheat-mode in which they keep
the PCI bus busy until they are ready to accept new
commands, rather forcing a retry.  Figures of up to
twenty milliseconds have been mentioned.  Your X server
*may* support the `PCIRetry' config option which will
defeat this.

Info:

http://www.lib.uaa.alaska.edu/linux-kernel/archive/2001-Week-02/1566.html
http://www.zefiro.com/vgakills.txt
http://www.zdnet.com/pcmag/news/trends/t980619a.htm
http://www.research.microsoft.com/~mbj/papers/tr-98-29.html

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