[alsa-devel] Sample format coversion bug?

Trent Piepho xyzzy at speakeasy.org
Mon Oct 29 19:47:12 CET 2007

On Mon, 29 Oct 2007, Alexander E. Patrakov wrote:
> Even though mmap seems to be supported in the driver source (judging
> from .info = SNDRV_PCM_INFO_MMAP | other flags), I could not figure out
> the parameters that work. Moreover, the driver seems to accept the same
> hardware parameters without the mmap, and I could not find parameters
> that the driver accepts for mmap.

I do not think the saa7134-alsa driver supports mmap.  The cx88-alsa driver
also claimed to support mmap, but it never worked until I fixed it.  It's
pretty clear that the code in saa7134-alsa was based on the same code as
cx88-alsa, so it's likely it has the same bug.

> One more question: since plug doesn't work at all on devices without
> mmap available, does this mean that I should scrap my original idea
> about using plug to convert everything into S24?

Does plug require mmap?  It does it just require that devices which claim
to support mmap actually work in mmap mode?

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