We are developing a VOIP phone. I upgraded my ubuntu 9.10 Karmic last thursday. Since, I can't get any audio playback from pulseaudio or very crappy one. There is several playback buffer underrun occuring. The Alsa plug-in still work well. Before that upgrade, everything was working just fine. I have pulseaudio and my application running on a Jaunty 9.10 and there is no problems. Looking at the Latency Control (http://pulseaudio.org/wiki/LatencyControl?version=17): I first make sure that PA runs timer scheduling mode (tsched=1) for ALSA devices. Is this parameter is the /etc/pulse/daemon.conf "realtime-scheduling = yes" Uncommenting realtime-scheduling = yes realtime-priority = 5 had no effect. Using these pstream attributes provide me these debug messages in pulseaudio: attributes->maxlength = (uint32_t) -1; attributes->tlength = 4096; attributes->prebuf = (uint32_t) -1; attributes->minreq = (uint32_t) -1; attributes->fragsize = (uint32_t) -1; pa_stream_connect_playback( s , NULL , attributes, PA_STREAM_ADJUST_LATENCY, &_volume, NULL) I: sink-input.c: media.name = "SFLphone out" I: sink-input.c: application.name = "SFLphone" I: sink-input.c: native-protocol.peer = "UNIX socket client" I: sink-input.c: native-protocol.version = "16" I: sink-input.c: media.role = "phone" I: sink-input.c: application.process.id = "10476" I: sink-input.c: application.process.user = "alexandresavard" I: sink-input.c: application.process.host = "alexandresavard-desktop" I: sink-input.c: application.process.binary = "lt-sflphoned" I: sink-input.c: application.language = "C" I: sink-input.c: window.x11.display = ":0.0" I: sink-input.c: application.process.machine_id = "760a77c32e810552e0ee9e6a4967c274" I: sink-input.c: application.process.session_id = "760a77c32e810552e0ee9e6a4967c274-1256332458.764918-577634043" I: sink-input.c: module-stream-restore.id = "sink-input-by-media-role:phone" I: protocol-native.c: Requested tlength=46.44 ms, minreq=20.00 ms D: protocol-native.c: Adjust latency mode enabled, configuring sink latency to half of overall latency. D: alsa-sink.c: Cutting sleep time for the initial iterations by half. D: alsa-sink.c: Cutting sleep time for the initial iterations by half. D: memblockq.c: memblockq requested: maxlength=4194304, tlength=4940, base=2, prebuf=3178, minreq=1764 maxrewind=0 D: memblockq.c: memblockq sanitized: maxlength=4194304, tlength=4940, base=2, prebuf=3178, minreq=1764 maxrewind=0 I: protocol-native.c: Final latency 72.01 ms = 16.01 ms + 2*20.00 ms + 16.00 ms D: alsa-sink.c: Cutting sleep time for the initial iterations by half. D: alsa-sink.c: Latency set to 16.00ms D: alsa-sink.c: hwbuf_unused=62716 D: alsa-sink.c: setting avail_min=16033 D: alsa-sink.c: Requesting rewind due to latency change. D: alsa-sink.c: Requested to rewind 65536 bytes. D: alsa-sink.c: Limited to 63808 bytes. D: alsa-sink.c: before: 15952 D: alsa-sink.c: after: 15952 D: alsa-sink.c: Rewound 63808 bytes. D: sink.c: Processing rewind... D: sink-input.c: Have to rewind 63808 bytes on render memblockq. D: source.c: Processing rewind... D: core-subscribe.c: Dropped redundant event due to change event. D: reserve-wrap.c: Device lock status of reserve-monitor-wrapper at Audio0 changed: not busy D: protocol-native.c: Requesting rewind due to end of underrun. D: alsa-sink.c: Requested to rewind 65536 bytes. D: alsa-sink.c: Limited to 1220 bytes. D: alsa-sink.c: before: 305 D: alsa-sink.c: after: 305 D: alsa-sink.c: Rewound 1220 bytes. D: sink.c: Processing rewind... D: sink-input.c: Have to rewind 1220 bytes on render memblockq. D: source.c: Processing rewind... D: protocol-native.c: Underrun on 'SFLphone out', 0 bytes in queue. D: protocol-native.c: Requesting rewind due to end of underrun. D: alsa-sink.c: Requested to rewind 196 bytes. D: alsa-sink.c: Limited to 196 bytes. D: alsa-sink.c: before: 49 D: alsa-sink.c: after: 49 D: alsa-sink.c: Rewound 196 bytes. D: sink.c: Processing rewind... D: sink-input.c: Have to rewind 196 bytes on render memblockq. D: source.c: Processing rewind... D: protocol-native.c: Requesting rewind due to end of underrun. D: alsa-sink.c: Requested to rewind 196 bytes. D: alsa-sink.c: Limited to 196 bytes. D: alsa-sink.c: before: 49 D: alsa-sink.c: after: 49 D: alsa-sink.c: Rewound 196 bytes. D: sink.c: Processing rewind... D: sink-input.c: Have to rewind 196 bytes on render memblockq. D: source.c: Processing rewind... D: protocol-native.c: Underrun on 'SFLphone out', 0 bytes in queue. D: protocol-native.c: Requesting rewind due to end of underrun. D: alsa-sink.c: Requested to rewind 328 bytes. D: alsa-sink.c: Limited to 328 bytes. D: alsa-sink.c: before: 82 D: alsa-sink.c: after: 82 D: alsa-sink.c: Rewound 328 bytes. D: sink.c: Processing rewind... D: protocol-native.c: Requesting rewind due to end of underrun. D: alsa-sink.c: Requested to rewind 328 bytes. D: alsa-sink.c: Limited to 328 bytes. D: alsa-sink.c: before: 82 D: alsa-sink.c: after: 82 D: alsa-sink.c: Rewound 328 bytes. D: sink.c: Processing rewind... D: sink-input.c: Have to rewind 328 bytes on render memblockq. D: source.c: Processing rewind... D: protocol-native.c: Requesting rewind due to end of underrun. D: alsa-sink.c: Requested to rewind 328 bytes. D: alsa-sink.c: Limited to 328 bytes. D: alsa-sink.c: before: 82 D: alsa-sink.c: after: 82 D: alsa-sink.c: Rewound 328 bytes. D: sink.c: Processing rewind... D: sink-input.c: Have to rewind 328 bytes on render memblockq. D: source.c: Processing rewind... D: protocol-native.c: Underrun on 'SFLphone out', 0 bytes in queue. D: protocol-native.c: Requesting rewind due to end of underrun. D: alsa-sink.c: Requested to rewind 80 bytes. D: alsa-sink.c: Limited to 80 bytes. D: alsa-sink.c: before: 20 D: alsa-sink.c: after: 20 D: alsa-sink.c: Rewound 80 bytes. D: sink.c: Processing rewind... D: sink-input.c: Have to rewind 80 bytes on render memblockq. D: source.c: Processing rewind... D: protocol-native.c: Requesting rewind due to end of underrun. D: alsa-sink.c: Requested to rewind 80 bytes. D: alsa-sink.c: Limited to 80 bytes. D: alsa-sink.c: before: 20 D: alsa-sink.c: after: 20 D: alsa-sink.c: Rewound 80 bytes. D: sink.c: Processing rewind... D: sink-input.c: Have to rewind 80 bytes on render memblockq. D: source.c: Processing rewind... D: protocol-native.c: Underrun on 'SFLphone out', 0 bytes in queue. Then I chaged parameters to: attributes->maxlength = 88200; attributes->tlength = 4096; attributes->prebuf = 4096; attributes->minreq = 2048; attributes->fragsize = 4096; pa_stream_connect_playback( s , NULL , attributes, PA_STREAM_ADJUST_LATENCY, &_volume, NULL) I: sink-input.c: media.name = "SFLphone out" I: sink-input.c: application.name = "SFLphone" I: sink-input.c: native-protocol.peer = "UNIX socket client" I: sink-input.c: native-protocol.version = "16" I: sink-input.c: media.role = "phone" I: sink-input.c: application.process.id = "8208" I: sink-input.c: application.process.user = "alexandresavard" I: sink-input.c: application.process.host = "alexandresavard-desktop" I: sink-input.c: application.process.binary = "lt-sflphoned" I: sink-input.c: application.language = "C" I: sink-input.c: window.x11.display = ":0.0" I: sink-input.c: application.process.machine_id = "760a77c32e810552e0ee9e6a4967c274" I: sink-input.c: application.process.session_id = "760a77c32e810552e0ee9e6a4967c274-1256332458.764918-577634043" I: sink-input.c: module-stream-restore.id = "sink-input-by-media-role:phone" I: protocol-native.c: Requested tlength=46.44 ms, minreq=23.22 ms D: protocol-native.c: Adjust latency mode enabled, configuring sink latency to half of overall latency. D: alsa-sink.c: Cutting sleep time for the initial iterations by half. D: alsa-sink.c: Cutting sleep time for the initial iterations by half. D: memblockq.c: memblockq requested: maxlength=88200, tlength=4140, base=2, prebuf=2094, minreq=2048 maxrewind=0 D: memblockq.c: memblockq sanitized: maxlength=88200, tlength=4140, base=2, prebuf=2094, minreq=2048 maxrewind=0 I: protocol-native.c: Final latency 47.44 ms = 0.50 ms + 2*23.22 ms + 0.50 ms D: alsa-sink.c: Cutting sleep time for the initial iterations by half. D: alsa-sink.c: Latency set to 0.50ms D: alsa-sink.c: hwbuf_unused=65448 D: alsa-sink.c: setting avail_min=16374 D: alsa-sink.c: Requesting rewind due to latency change. D: alsa-sink.c: Requested to rewind 65536 bytes. D: alsa-sink.c: Limited to 65172 bytes. D: alsa-sink.c: before: 16293 D: alsa-sink.c: after: 16293 D: alsa-sink.c: Rewound 65172 bytes. D: sink.c: Processing rewind... D: sink-input.c: Have to rewind 65172 bytes on render memblockq. D: source.c: Processing rewind... D: core-subscribe.c: Dropped redundant event due to change event. D: reserve-wrap.c: Device lock status of reserve-monitor-wrapper at Audio0 changed: not busy D: protocol-native.c: Requesting rewind due to end of underrun. D: alsa-sink.c: Requested to rewind 65536 bytes. D: alsa-sink.c: Limited to 44 bytes. D: alsa-sink.c: before: 11 D: alsa-sink.c: after: 11 D: alsa-sink.c: Rewound 44 bytes. D: sink.c: Processing rewind... D: sink-input.c: Have to rewind 44 bytes on render memblockq. D: source.c: Processing rewind... I: alsa-sink.c: Underrun! I: alsa-sink.c: Increasing minimal latency to 1.00 ms D: alsa-sink.c: Latency set to 1.00ms D: alsa-sink.c: hwbuf_unused=65360 D: alsa-sink.c: setting avail_min=16363 D: protocol-native.c: max_request changed, trying to update from 4140 to 4184. D: protocol-native.c: Notifying client about increased tlength D: alsa-sink.c: Latency set to 1.00ms D: alsa-sink.c: hwbuf_unused=65360 D: alsa-sink.c: setting avail_min=16363 I: alsa-sink.c: Underrun! I: alsa-sink.c: Increasing minimal latency to 2.00 ms D: alsa-sink.c: Latency set to 2.00ms D: alsa-sink.c: hwbuf_unused=65184 D: alsa-sink.c: setting avail_min=16341 D: protocol-native.c: max_request changed, trying to update from 4184 to 4272. D: protocol-native.c: Notifying client about increased tlength D: alsa-sink.c: Latency set to 2.00ms D: alsa-sink.c: hwbuf_unused=65184 D: alsa-sink.c: setting avail_min=16341 I: alsa-sink.c: Underrun! I: alsa-sink.c: Increasing minimal latency to 4.00 ms D: alsa-sink.c: Latency set to 4.00ms D: alsa-sink.c: hwbuf_unused=64832 D: alsa-sink.c: setting avail_min=16297 D: protocol-native.c: max_request changed, trying to update from 4272 to 4448.
