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On Sat, 30 Jan 2010, Louise Hoffman wrote:

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Dear ALSA developers,

When I compile ALSA's pcm_min.c[0] example with

gcc -Wall -lasound pcm_min.c -o pcm_min

Everything is fine, but running it, I get the white noise as expected, but I also get this warning/error:

Short write (expected 16384, wrote 7616)

It was a bug in alsa-lib. I fixed it in patch bellow. Thank you for your report.

http://git.alsa-project.org/?p=alsa-lib.git;a=commitdiff;h=2e48439ad93f6c8d9... http://git.alsa-project.org/?p=alsa-lib.git;a=commitdiff;h=2e48439ad93f6c8d99a2d72928ac71285b5211bb

Add snd_pcm_dump() after call snd_pcm_set_params in pcm_min.c

The start threshold is equal to buffer size , so there should be a short write at the second write since 16384 + 7616 = 24000 ( start threshold )

your patch had changed the behaviour

./pcm_min ALSA <-> PulseAudio PCM I/O Plugin Its setup is: stream : PLAYBACK access : RW_INTERLEAVED format : U8 subformat : STD channels : 1 rate : 48000 exact rate : 48000 (48000/1) msbits : 8 buffer_size : 24000 period_size : 6000 period_time : 125000 tstamp_mode : NONE period_step : 1 avail_min : 6000 period_event : 0 start_threshold : 24000 stop_threshold : 24000 silence_threshold: 0 silence_size : 0 boundary : 1572864000 state = 2 write 16384 frames state = 2 write 16384 frames state = 3 write 16384 frames state = 3 write 16384 frames state = 3