[uml-devel] ALSA and host audio relay in UML

[uml-devel] ALSA and host audio relay in UML

[Luca Saiu]

Hello Jeff, and all the fellow UML developers.
I think this is the first time we directly communicate. First of all we 
wish to thank you for your terrific work on UML, from which our project, 
Marionnet, is heavily dependent.

We would like to add a "virtual phone" device to Marionnet, implemented 
on a UML virtual machine running Ekiga or Linphone. We have several 
problems in using sound daemons with both Ekiga and Linphone, so instead 
of having a sound daemon on the host machine, which would be the 
simplest solution, we are essentially forced to use host audio relaying. 
That feature works very well, but as far as I can understand from the 
source and from my tests, it's limited to OSS. Recent versions of ALSA, 
by contrast, are better supported by modern software such as Ekiga and 
easily allow multiplexing. We wouldn't strictly need multiplexing on 
each single virtual machine, but at least more than one virtual machine 
at a time would need to be able to use the same host sound device, both 
for input and for output.
Unfortunately, this is not possible at the moment.

Is ALSA relaying hard to implement in UML? We honestly don't know that 
part of the kernel, and we were wondering whether some other solution 
may be simpler. Is there hope to have ALSA support in UML in the future?

Thanks in advance,

-- 
Luca Saiu
http://www-lipn.univ-paris13.fr/~saiu
GNU epsilon: http://www.gnu.org/software/epsilon
Marionnet:   http://www.marionnet.org

-------------------------------------------------------------------------
This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
Build the coolest Linux based applications with Moblin SDK & win great prizes
Grand prize is a trip for two to an Open Source event anywhere in the world
http://moblin-contest.org/redirect.php?banner_id=100&url=/
_______________________________________________
User-mode-linux-devel mailing list
User-mode-linux-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel

Re: [uml-devel] ALSA and host audio relay in UML

[Jeff Dike]

On Mon, Jul 28, 2008 at 04:31:06PM +0200, Luca Saiu wrote:
> That feature works very well, but as far as I can understand from the 
> source and from my tests, it's limited to OSS. 

The host audio driver just uses the host's /dev/sound/dsp and
/dev/sound/mixer.  Are these OSS-specific?  If so, and you want to use
different host interfaces, it should be simple to add support for them
to the driver, which is about the simplest possible UML driver.  If
there are equivalent ALSA device files with different names, UML has
dsp= and mixer= flags to allow it to use different devices.

     	 	      	 Jeff

-- 
Work email - jdike at linux dot intel dot com

-------------------------------------------------------------------------
This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
Build the coolest Linux based applications with Moblin SDK & win great prizes
Grand prize is a trip for two to an Open Source event anywhere in the world
http://moblin-contest.org/redirect.php?banner_id=100&url=/
_______________________________________________
User-mode-linux-devel mailing list
User-mode-linux-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel