[LAU] RME Multiface II via direct Alsa (no Jack)

[Brent Busby]

On Thu, 24 Dec 2009, Paul Davis wrote:

> On Wed, Dec 23, 2009 at 10:14 PM, Brent Busby <brent at keycorner.org> wrote:
>> From what I've gathered online, I think what I need may be a .asoundrc
>> file.  Then again, maybe not:  The asoundrc documentation says that what
>> it's doing is basically mapping device/channel names found in
>> /proc/asound/devices (sort of the same info you get from 'aplay -L') to
>> custom names and routings.  Problem is, the 18 channels of the Multiface
>> all show up as *one* PCM device here!  Where are all my subdevices?  For
>> that matter, if I did even try to use that one PCM, which channel would
>> it come out of?  (Haven't tried it...not really that curious.)
>
> the RME hammerfall/hdsp and related devices have a single PCM
> subdevice. you cannot access specific channels of that subdevice via a
> device name unless you set up a "route" ALSA plugin pseudo-device
> (google will reveal more). Even when you do, using that device will
> "own" the entire PCM device - you can't have app A on channels 1 and 2
> and app B on channels 3 and 4. My recollection is that if you use
> plughw:N to access the device, and just send it 2 channels, they will
> be replicated across all channels.
>
>> Other people have asked this before, but most such threads seem to
>> always come to "just use Jack."  Is it impossible to directly access
>> these devices from Alsa?  I'm not wanting anything fancy here.
>
> Actually, you might want something fancy. It sounds if you want
> per-app access to specific channels. ALSA doesn't do that by itself.

It'd be useful, but actually all I'm wanting is to be able to output 
sound for awhile.  I don't need to be able to use multiple apps at once, 
and it won't be a problem for an app to temporarily have control of the 
whole Hammerfall.  It's just for casual playback situations.  I'll 
lookup the Alsa setup configs you mentioned.

-- 
+ Brent A. Busby	 + "We've all heard that a million monkeys
+ UNIX Systems Admin	 +  banging on a million typewriters will
+ University of Chicago	 +  eventually reproduce the entire works of
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+ James Franck Institute +  we know this is not true." -Robert Wilensky