[pulseaudio-discuss] Why tsched disabled when I use module-alsa-sink with 'mmap=0 tsched=1' parameters?

Tanu Kaskinen tanu.kaskinen at linux.intel.com
Fri Dec 19 05:15:05 PST 2014

On Thu, 2014-12-11 at 21:49 +0900, 김정연 wrote:
> Dear developers,
> I have question something about selecting logic between timer-based
> and IRQ scheduling.
> When I tried to load 'module-alsa-sink' with 'mmap=0 tsched=1'
> parameters, tsched(timer-based scheduling) becomes disabled by below
> codes.
> It seems tsched is allowed only mmap supported ALSA devices. Why
> tsched disabled while use non-mmap driven ALSA?

Because rewinding is not available in non-mmap mode. That is, it's not
possible to rewrite previously written data in non-mmap mode. In
timer-based scheduling mode PulseAudio uses bigger buffer size, which
causes problems if rewinding isn't available.


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