[pulseaudio-discuss] [PATCH] Do not use tsched watermark if tsched is disabled

David Henningsson david.henningsson at canonical.com
Wed Aug 18 01:28:53 PDT 2010

2010-08-17 21:10, Colin Guthrie skrev:
> 'Twas brillig, and David Henningsson at 17/08/10 19:20 did gyre and gimble:
>> According to what you say in that bug, you could reproduce it yourself
>> by setting tsched=0, so I'm eager to hear if this fix fixes your issue
>> as well.
> Yeah I was able to reproduce it pretty easily with the chordtest.sh
> script attached to the bug. After the third tone, it started to sound
> terribly distored.
> After applying your patch, I tried several times and got a perfect run
> each time :)


The patch is against stable-queue, and Raymond commented that git master
has a slightly different way of solving the problem. To compare them:

* Pierre-Louis Bossart's version in git master sets a fixed margin of
256 bytes, (configurable if you load the sink manually, i e not through

* My version sets a fixed margin of 20 ms.

* My version only changes non-tsched devices and keeps tsched having a
margin of the current watermark, whereas Bossart's version changes both.

I think a margin should be based on milliseconds rather than bytes (the
amount of bytes varies with amount of channels, which means that we
might get problems when people switch to surround output).

I don't have an opinion on whether a fixed margin or watermark-based
margin is better for tsched sinks.

David Henningsson, Canonical Ltd.

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