[alsa-devel] [RFC] ALSA: add new alsa control byte extended

Vinod Koul vinod.koul at intel.com
Fri Nov 29 14:28:25 CET 2013

On Fri, Nov 29, 2013 at 01:11:53PM +0000, Charles Keepax wrote:
> > I am leading more towards adding new ioctl for this along with new ones for
> > enumerating controls. Then additional support for alsa-lib and tinyalsa.
> > That way existing tinymix, amxier can see these as controls while not disturbing
> > existing apps. I dont think we need save and restor, then alsactl need not be
> > modified.
> It does feel a little odd to have this data set through a
> different interface to other existing control data, but I guess
> anything we do does have to be very careful around upsetting
> existing user-space code.
Am thinking users and driver shouldn't feel that it is different. The approach i
am leaning now is adding three ioctls, for enumerating, reading and then
writing. The tinyalsa and alsa-lib should also enumerate these new ones.  But we
don't impact ABI so old users/apps won't change.  Similarly on kernel side we
still treat these as kcontrols and drivers use existing infrastructure to manage


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