[pulseaudio-discuss] [PATCH] alsa: Disable timer-scheduling for PCMs with the BATCH flag

[Raymond Yau]

2013/12/1 Lars-Peter Clausen <lars at metafoo.de>

> 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.
>
>
If the playback position is reported in steps instead of monotonic
increasing ?

does this mean that you also need to increase rewind_safeguard to one
period or modifiy snd_pcm_rewindable ?
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