open issue documentation: update sound page.

IRC, freenode, #hurd, 2013-09-01

<rekado> I'm new to the hurd but I'd love to learn enough to work on sound
  support.
<rekado>
  http://darnassus.sceen.net/~hurd-web/community/gsoc/project_ideas/sound/
  says drivers should be ported to GNU Mach as a first step.
<rekado> Is this information still current or should the existing Linux
  driver be wrapped with DDE instead?
<auronandace> if i recall correctly dde is currently only being used for
  network drivers. i'm not sure how much work would be involved for sound
  or usb

IRC, freenode, #hurd, 2013-09-02

<rekado> The sound support proposal
  (http://darnassus.sceen.net/~hurd-web/community/gsoc/project_ideas/sound/)
  recommends porting some other kernel's sound driver to GNU Mach.  Is this
  still current or should DDE be used instead?
<pinotree> rekado: dde or anything userspace-based is generally preferred
<braunr> rekado: both are about porting some other kernel's sound driver
<braunr> dde is preferred yes
<rekado> This email says that sound drivers are already partly working with
  DDE: http://os.inf.tu-dresden.de/pipermail/l4-hackers/2009/004291.html
<rekado> So, should I just try to get some ALSA kernel parts to compile
  with DDE?
<pinotree> well, what is missing is also the dde←→hurd glue
<braunr> rekado: there is also a problem with pci arbitration
<rekado> pinotree: I assumed DDEKit works with the hurd and we could use
  any DDE/<other kernel> glue code with it
* rekado looks up pci arbitration
<pinotree> only for networking atm
<rekado> ah, I see.