Re: [ecasound] Problem with 2.7.0

From: Kai Vehmanen <kvehmanen@email-addr-hidden>
Date: Tue Oct 20 2009 - 00:47:11 EEST


On Mon, 19 Oct 2009, Pierre Lorenzon wrote:

>> hmm, ok, I have one hypothesis. Here's one snapshot, let me
>> know if it helps:
> Yes it does ! The problem no longer exists with this version.

ok, great, that is really good news. I now wrote a longer mail about this
to ALSA list:

The good news is that this bug should not hit too many people. Most ALSA
PCMs support power-of-two period-sizes (-b:1024, -b:128, ...), and in
these cases no glitches should not occur.

In your specific case, I think the PCM doesn't support -b:1024 but
something close, as the block/period size. Now due to the bug this results
in discontinuity at every block, leading to glitches at a rate of ~20Hz
when playing 44.1kHz audio. This matches pretty closely what you

>> Also, I'd be interested to know which version of alsa-lib
> 1.0.13
>> (libasound) do you have, and which kernel version?

These match as well. These still have the old implementation of
snd_pcm_sw_params_set_xfer_align both in alsa-lib and in kernel.

Thanks for helping to track this down! I'll release 2.7.1 soonish with
this fix (and possibly a few others as well) included.

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Received on Tue Oct 20 04:15:01 2009

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