Re: Assigning sound card to specific X display - the chroot+bind-mount way

[Ken M. <ke...@th...>]

On Sun, 2005-06-05 at 17:05 -0400, Ken McCord wrote:

> On Fri, 2005-06-03 at 11:03 +0200, Helge Hafting wrote: 
> 
> > Aivils wrote:
> > 
> > >On Thursday 02 June 2005 04:27, Ken McCord wrote:
> > >  
> > >
> > >>I'm running a dual-head setup using Debian unstable + the x.org packages
> > >>from Ubuntu.  I have two sound cards, and I'd like to assign each of
> > >>them
> > >>to a specific X display.  How can I do this?
> > >>
> 
> <snip>
> 
> > >
> > >Try out set up artsd under KDE or esd under GNOME . 
> > >
> > >Even if these software sound mixers like artsd or esd runs
> > >properly, then You cannot disable Java and Flash Player,
> > >which uses sound device directly.
> > >I open Java binary with hexedit and manulay replace
> > >/dev/dsp with fake non-existing device file for silence.
> > >  
> > >
> > There is a way.
> > One xserver can run in its own chroot.  The two servers can have
> > distinct /dev directories that way, where the two "dsp" files in the
> > distinct directories have different device numbers and so
> > refer to different sound devices.
> > Make a copy of /dev in /chroot/dev.  In there, make sure
> > "dsp" refers to the second soundcard instead of the first.
> > 
> > On a debian system "dsp" is a symlink to "dsp0".  Change it to
> > a link to "dsp1" instead.  On other systems you may have to
> > do something like "mv dsp1 dsp0".
> > 
> > Whatever the solution is, do the same for all other sound-related
> > files, such as "mixer" and so on.
> > 
> > 

<snip>

> > 
> 
> <snip>
> 
> > Helge Hafting
> 
> 
> I've played around with artsd and esd a bit more, and have been able
> to get /dev/dsp and /dev/dsp1 working,
> but there are problems.  Using esd, you can't use Gnome's 'Enable
> Sound Server Startup' in the 'Sound Preferences' dialog box as it
> starts another copy of esd.  I haven't been able to find where to set
> any options for this server (ie use the options I want to start the
> server).  Logging off and on again is problematic, and I've also seen
> times where my setting for ESPEAKER gets modified.
> 
> The idea of running the chroot is interesting.  But would I need to
> chroot the xserver only, or parts of Gnome as well?
> 
> Thanks,
> 
> Ken


Never mind.  I've been able to set up the chroot environment, and
actually get the /dev/dsp files working correctly.  I was going down the
wrong path at first, trying to start X in the chroot environment with
using -indirect or -query.  That just gave me the same /dev structure I
didn't want.  Removing that from the startx command did the trick.

I still need to clean up the setup, the interface with gdm and getting
it to start automagically on boot, but it looks promising.

Thanks,

Ken