[alsa-devel] Possible message repeat

Brent Weatherall brentweatherall at gmail.com
Mon Jun 25 17:02:58 CEST 2012

Clemens.  I just wanted to clarify the situation.  It seemed you were
hinting at the possibility, but I was not 100% sure.  Thank you for
clearing that up.

On Mon, Jun 25, 2012 at 2:49 AM, Clemens Ladisch <clemens at ladisch.de> wrote:

> Brent Weatherall wrote:
> > our goal is to specify a special XU that WOULD require vendors
> > supporting it to modify their firmware.  We fully expect a vendor to
> > modify their firmware to support our specification.  That being said,
> > is there a simple way to use ALSA to communicate with a vendor
> > specific XU as long as the software understands the XU?  For example,
> > in the video4linux2 world, we can specify a UVC XU with a set of
> > controls for special processing, then vendors that want to support it
> > modify their firmware to support it.  Then anyone can use our custom
> > user-space drivers to easily talk to the video device.  V4L2 has
> > controls made for using XUs in this manner.
> The audio class specification does not define any mechanism for a device
> to specify what those controls would be.  And because nobody has ever
> needed to use XUs so far, the current ALSA driver has no other way to
> create such controls.
> If you insist on not changing ALSA, you must bypass it.
> Regards,
> Clemens

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