[alsa-devel] aplay -M (mmap) omap

Takashi Iwai tiwai at suse.de
Fri Sep 7 13:26:05 CEST 2007

At Wed, 5 Sep 2007 18:04:30 -0500,
Lopez Cruz, Misael wrote:
> Hi,
> I'm experiencing kernel crashes in an omap platform when playing audio
> files with 'aplay -M' (mmap option) the second time a file is played.

The behavior depends on the alsa-lib setup.  Doesn't the default
config use dmix, right?  If so, it looks like an access to wrong
mapped pages.

> Any suggestion where to start debugging this? Is there a common cause
> for this failure?

Check substream->mmap_count.  It's incremented/decremented in
snd_pcm_mmap_data_open/close in include/pcm.h.  It has to reach to
zero properly with closing a PCM stream.


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