[alsa-devel] [PATCH 4/5] intelhdmi - add channel mapping for typical configurations

Wu Fengguang fengguang.wu at intel.com
Fri Dec 11 13:05:18 CET 2009

On Fri, Dec 11, 2009 at 03:00:29PM +0800, Takashi Iwai wrote:
> At Fri, 11 Dec 2009 12:28:36 +0800,
> Wu Fengguang wrote:
> > 
> > IbexPeak is the first Intel HDMI audio codec to support channel mapping.
> > 
> > Currently the outstanding problem is, the HDMI channel order do not
> > agree with that of ALSA.  This patch presents workaround for some
> > typical use cases. It gives priority to the typical ALSA surround
> > configurations, and defines channel mapping for them.
> This looks good.  At least, this can reduce confusions.

Thank you.

> > We may need better kernel+userspace interactive channel mapping scheme.
> > For example, in current scheme if user plays with the surround50 device,
> > the kernel is unaware of this and will still select the surround41
> > channel allocation and channel mapping..
> Yes, more flexible channel mapping is on my TODO list.
> I have a half-finished patch series, but need to rebase and brush up.
> Let's fix it for 2.6.34.

That would be great. The rational I do this patch is, even if we have
some user-space channel mapping facility, it still benefits to be able
to use the hardware capability -- which helps saving power :)


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