[alsa-devel] pcm->private_data is NULL in alsa core!!

Pharaoh . pharaoh137 at gmail.com
Sat Jun 16 14:50:46 CEST 2007

I am writing an alsa driver for my omap based board. I am testing it using
cat /dev/audio currently, i.e. I have OSS emulation turned on. This is
an initial round of testing and I will use alsa-libs and utils later.

My problem is:

I have set the pcm->private_data = my_chip after registering the pcm ops,
after referring various standard drivers in alsa tree. My module is
insmoded properly but after I do snd_card_register(card) the
pcm->private_data is corrupted !! Before this step, the
pcm->private_data is intact.  But after looking at the
snd_card_register(), I realized that it doesn't even touch the pcm

So, when I cat the device I get huge segfault in
snd_pcm_attach_substream(), since pcm->private_data is NULL but
surprisingly all the other fields are intact in pcm pointer.

 Even the OSS code doesn't touch the pcm pointer, what must be wrong?
I have checked my source atleast 5 times and couldn't find anything in it.


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