Linked by Thom Holwerda on Thu 7th Jul 2011 17:36 UTC, submitted by vivainio
Linux Linux.FR has an interview with Lennart Poettering of PulseAudio and systemd fame (among others). Regarding PulseAudio: "I can understand why people were upset, but quite frankly we didn't really have another option than to push it into the distributions when we did. While PulseAudio certainly wasn't bug-free when the distributions picked it up the majority of issues were actually not in PulseAudio itself but simply in the audio drivers. PulseAudio's timer-based scheduling requires correct timing information supplied by the audio driver, and back then the drivers weren't really providing that. And that not because the drivers were really broken, but more because the hardware was, and the drivers just lacked the right set of work-arounds, quirks and fixes to compensate for it."
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RE[6]: Broken audio hardware
by Alfman on Fri 8th Jul 2011 05:11 UTC in reply to "RE[5]: Broken audio hardware"
Alfman
Member since:
2011-01-28

_txf_,

Thank you for the link, definately informative. However it seems to contradict Lennart's recent statements in a few places. Particularly:

"We become much less dependant on what the sound hardware provides us with. We can configure wakeup times that are independant from the fragment settings that the hardware actually supports."

From your link, the main difference from traditional audio processing is that "pulse audio glitch-free" opts not to use sound card timers/IRQs and use system timers/IRQs instead to provide even lower latency than is available through the sound card. Pulse audio can therefor update the DMA buffer at any time without synching with the sound card timer.

This is great (no sarcasm), but I don't get why he claims a break in compatibility was necessary. What technical reason is there that pulse audio could not revert to sound card IRQs instead of breaking things? In the absolute worst case, this would have resulted in higher latency, which is at most a minor annoyance.

I'm not understanding the technical reason that pulse audio couldn't revert to using sound card IRQs as they were intended instead of breaking sound support all together? Can someone clear this up?

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