[alsa-devel] about sound/core/pcm_lib.c:1997: capture read error (DMA or IRQ trouble?)

[Clemens Ladisch]

Akio wrote:
> Clemens Ladisch <cladisch <at> fastmail.net> writes:
> > Akio write:
> > > after long time amr-wb codec loopback test. (above 90 hours)
> > > I got the following kernel message.  it comes from snd_pcm_lib_read1()
> > > function. 
> > > ALSA sound/core/pcm_lib.c:1997: capture read error (DMA or IRQ trouble?)
> > 
> > This error indicates that no interrupt has been received for ten
> > seconds.
> > 
> > I would have guessed that some 32-bit counter has overflowed, but at
> > 48 kHz, a frame counter would overflow after slightly less than
> > 25 hours.
> 
> Thanks for Clemens. Could you tell me the counter's name and which layer does it?
> in alsa driver or in alsa lib or in alsa core module?

I'm not aware of any such bug in the ALSA framework.  I'd guess this is
some problem with your driver.

What sample frequency are you using?

> snd_pcm_prepare does not work.

What error does it return?


Regards,
Clemens