Re: [libvirt] [PATCH] qemu: Allow using regular audio backends with VNC

On Thu, May 20, 2010 at 12:04:04PM -0400, Cole Robinson wrote: > Currently all host audio backends are disabled if a VM is using VNC, in > favor of the QEMU VNC audio extension. Unfortunately no released VNC > client supports this extension, so users have no way of getting audio > to work if using VNC. > > Add a new config option in qemu.conf which allows changing libvirt's > behavior, but keep the default intact. > > Signed-off-by: Cole Robinson <crobinso(a)redhat.com&gt; > --- > src/qemu/qemu.conf | 10 ++++++++++ > src/qemu/qemu_conf.c | 17 ++++++++++++----- > src/qemu/qemu_conf.h | 2 ++ > 3 files changed, 24 insertions(+), 5 deletions(-) > > diff --git a/src/qemu/qemu.conf b/src/qemu/qemu.conf > index 3da332f..fec946d 100644 > --- a/src/qemu/qemu.conf > +++ b/src/qemu/qemu.conf > @@ -168,3 +168,13 @@ > # be assigned to guests. > # > # relaxed_acs_check = 1 > + > + > +# QEMU implements anextension for providing audio over a VNC connection, > +# though if your VNC client does not support it, your only chance for getting > +# sound output is through regular audio backends. By default, libvirt will > +# disable all QEMU sound backends if using VNC, since they can cause > +# permissions issues. Enabling this option will make libvirtd honor the > +# QEMU_AUDIO_DRV environment variable when using VNC. > +# > +# vnc_enable_audio_backend = 0 I think this would be better named as 'vnc_allow_host_audio' since its not toggling VNC audio, just whether it is allowed to use the host audio drivers.

NB, even with this toggled things are unlikely to magically 'just work'. If QEMU is running as 'qemu' user ID, that user won't have any permissions to use /dev/snd/* devices. And if running as 'root' then pulseaudio won't autospawn so will need to be run manually.