On 2011-04-22 01:25, Raymond Yau wrote:
2011/4/21 David Henningssondavid.henningsson@canonical.com
Due to a round-off error, snd_pcm_avail could in some cases return 0 even though more data could be written to the stream.
This was discovered by Maarten Lankhorst [1], and there is also a test program available that triggers this error [2].
[1] https://tango.0pointer.de/pipermail/pulseaudio-discuss/2011-April/009935.htm...
[2] https://tango.0pointer.de/pipermail/pulseaudio-discuss/attachments/20110420/...
if the test program can force under-run occur with "hw" device and "pulse" device with his patch in https://tango.0pointer.de/pipermail/pulseaudio-discuss/2011-April/009918.htm...
Is it normal that underrun does not occur with the test program and your patch
Yes; underruns are not reported to the application due to the risk of the underrun being obsolete at that time. As for Maarten's patch in the post you refer to,
1) if underruns are being reported (this is configurable), it might be a good idea to call "pulse_start".
2) it changes underruns to being reported by default, which is what I'm opposed to.