[alsa-devel] clarification on mmap

Takashi Iwai tiwai at suse.de
Mon Feb 23 16:27:13 CET 2009

At Mon, 23 Feb 2009 18:59:11 +0530,
Harsha, Priya wrote:
> Hi,
> I have a question on mmap. If I give my .info to be _MMAP and
> _MMAP_VALID. Will ALSA framework internally take care of mmap-ing
> the kernel buffer that has been pre-allocated in the .probe call? Do
> I need to do anything special to mmap a kernel buffer into user
> space? Just accessing the runtime->dma_area would allow me to access
> user data right? 

Yes.  The buffers allocated via preallocator are supposed to be
mmappable, so you can simply pass _MMAP* flag there.


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