On 09/24/2010 09:11 AM, pl bossart wrote: >> For normal alsa playback, their typical values are 1024. Pulseaudio >> sets them to large values and maybe is not entirely depending on the >> poll. It may be setting some timer to wake up itself when the DMA >> buffer runs low on data. >> >> Anyway the pulseaudio's large buffer scheme makes possible the 61ms >> pa_simple_write(). Qemu is not expecting such a large latency. Its >> QEMU_PA_SAMPLES defaults to 1024, which can only hold up to >> 1024/48=21ms samples. So the 61ms delay will obviously overflow the >> "data push" based USB audio model.. > > The default PulseAudio configuration is 4 periods of 25 ms each. You > can reduce this if you want by changing the relevant fields in > /usr/etc/daemon.conf > -Pierre Note, I haven't looked at the delays in pa_simple_write, but I definitely see audio stops on the order of seconds, which could realistically only be caused by either starvation or entire buffers getting thrown out. -hpa
