Hey,

op 30-11-13 18:07, Lars-Peter Clausen schreef:
PCM Devices which have the BATCH flag set update the PCM pointer only with
period size granularity. Using timer based scheduling does not have any
advantage in this mode. For one devices which have that flag set usually update
the position pointer in software after getting the period interrupt. So
disabling the period interrupt is not possible for this kind of devices.
Furthermore writing to or reading from the buffer slice for the current period
is not possible since the position inside the buffer is not known. On the other
hand the tsched algorithm seems to get easily confused for this kind of
hardware, which results in garbled audio output. This typically means that timer
based scheduling needs to be manually disabled on systems with such devices.
Auto disabling tsched in this case allows these systems to run with the default
configuration.
This causes a regression on USB headphones with winepulse when using pulseaudio 
5.0.

The latency is set to 100 ms and never changed afterwards, when interactive 
applications are
run that require lower latency the latency is never lowered, and wine's dsound 
emulation will fail
because it expects a granularity of ~40-50 ms at most, depending on the 
application.

I believe that tsched can stay enabled, as long as we take care always to 
buffer at least 1 period_size.

~Maarten
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