ALSA: pcm: detect xruns in no-period-wakeup mode

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When period wakeups are disabled, successive calls to the pointer update
function do not have a maximum allowed distance, so xruns cannot be
detected with the pointer value only.

To detect xruns, compare the actually elapsed time with the time that
should have theoretically elapsed since the last update.  When the
hardware pointer has wrapped around due to an xrun, the actually elapsed
time will be too big by about hw_ptr_buffer_jiffies.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

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Clemens Ladisch 2010-11-18 09:43:52 +01:00 • committed by Takashi Iwai

parent 075140ea8b

commit 59ff878ffb

1 changed files with 16 additions and 2 deletions

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sound/core/pcm_lib.c

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