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

Colin Guthrie gmane at colin.guthr.ie
Wed Aug 18 01:41:49 PDT 2010

'Twas brillig, and David Henningsson at 18/08/10 09:28 did gyre and gimble:
> 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 :)
> \o/
> 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
> module-udev-detect).
> * 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.

I presume Pierre-Louis will comment in due course. I'm sure he'll see
this message.

I'm annoyed I didn't appreciate that his fix would likely address the
issue too when it was pushed, but such is life :D



Colin Guthrie

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