[alsa-devel] [PATCH 1/2] Remove definition for surround sound devices on ICE1712.

[Takashi Iwai]

At Wed, 21 Jan 2009 16:45:29 +0000,
Alan Horstmann wrote:
> 
> On Wednesday 21 January 2009 10:00, Takashi Iwai wrote:
> > At Tue, 20 Jan 2009 17:33:24 +0100,
> >
> > Diego E. 'Flameeyes' Pettenò wrote:
> > > Jaroslav Kysela <perex at perex.cz> writes:
> > > > Note that front and surround devices does not support automatic sample
> > > > conversion. Use plug:front, plug:surround40 etc. devices.
> > >
> > > Using the correct format, front:IDX should work with two channels sound
> > > files, and it doesn't, nor surround40:IDX works with four channels or
> > > surround71:IDX with eight channels.
> > >
> > > [I'm using IDX because I have it on :1 rather than :0]
> >
> > I thought plug:front:IDX works, at least on 1.0.19, too...
> 
> It does work here on older Alsa.

But, if it works with the latest version code, it makes no sense to
fix the config of that tree.  We aren't changing the old tree now.

> I think Diego's point though is that 'surround40:IDX' might be expected to be 
> a 4-channel stream, whereas it is as dependant on the hardware as 'hw:IDX' 
> is.  In the later case it is clear that the user must provide audio in 
> whatever format/channels the hardware uses.  However it is unexpected that eg 
> on ice1712 'surround40:IDX' requires a 10-channel playback stream and ignores 
> 6 of them, and will not play a 4-channel stream.
> 
> It is also not symetrical, so if you capture it has to be a 12-channel stream, 
> which it is then not possible to play without using the plug: devices.
> 
> Unless I am mistaken...

Right, ice1712 is tricky as is.  I myself feel having plug inside the
front, etc, definitions would be more intuitive.  However, the plug
over plug doesn't (didn't? -- need checks) work.  And, the definition
should be as slim as possible.  These are counter arguments.


Takashi