[alsa-devel] snd-usb-audio syncronisation problem

Adrian Stancu adrian.stancu.82 at gmail.com
Fri Feb 22 10:51:16 CET 2008


I'm using an E-MU 0404 USB interface with the snd-usb-audio module
from alsa 1.0.16, operating in isochronous asynchronous mode. This
interface was producing very annoying click/pop sounds at regular
intervals during playback. Eventually I discovered that the
syncronisation mechanism telling the driver to send audio data faster
or slower to match the interface's consumption speed does not work as
expected, for some reason.

I did a very dirty hack within the source of this driver, simulating
the interface asking for data to be sent a little bit quicker, and
this almost fixed the problem *for me*. I really wish to debug this
issue further, to find what actually does not work as it should in
this feed-back mechanism. However this was the first time I dealt with
alsa source code, so I do not have much experience. Therefore, I
really need help with debugging this problem and maybe finding an
universal fix.

Thanks in advance,

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