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

Pharaoh . pharaoh137 at gmail.com
Sun Jun 17 17:45:31 CEST 2007


On 6/16/07, Pharaoh . <pharaoh137 at gmail.com> wrote:
> Hi
> 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
> pointer.
>
> 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.
>
> -pharaoh.
>



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