Saturday, May 21, 2011

Adding HDMI Audio to Ubuntu on the Acer Revo

Finally got around to attempting to get audio working through HDMI on
the little Acer Revo that I'd acquired a few months back. Turns out
it wasn't all that difficult, under Ubuntu 10.4.2.

The HDMI video worked when I plugged it in. It took a little while to
figure out that HDMI video wouldn't work unless I unplugged the SVGA
cable (this isn't mentioned in any online docs that I could find).

Audio took just a little more work than did video. First, I had to
update the nVidia driver and reboot. For some reason, version 173
doesn't support HDMI audio.

Next I added the following line to /etc/modprobe.d/alsa-base.conf
(this assumes that you have alsa-base installed):

  options snd-hda-intel model=auto

After that, I ran the following (as root) and rebooted after it was done:

  update-initramfs -k all -u

From there, I just needed to bring up the PulseAudio Volume Control
window, select the "Configuration" tab, and choose "Digital Stereo
(HDMI) Output" under the "Internal Audio" chooser. That's it.

There's a few minor problems with the new install. First, I can't
tell you what version of the proprietary driver. It's listed as
"(version current)", with the parens.

Second, where my monitor used to detect the video signal as 1920x1080
(using version 173 of the driver), it now detects the video signal as
"1080p". For some reason, this change causes the top and bottom of
the display to be off the screen (i.e., the Gnome panels are off the
screen). They're not visible unless I tell the Revo to use a 1440x900
resolution. I haven't yet decided which is the greater inconvenience:
having to switch headsets when listening to videos or the computer, or
having to employ a slightly less dense display resolution. For now, I
like not having to switch headsets. I'm still researching the video
resolution issue.

Lastly, and I'm not sure that it's actually a problem, I need to use
the monitor's control, vice the computer's, to control the audio
volume. It's going to take a little getting used to, reaching for the
remote control, vice the knob on my keyboard.

My thanks to Christopher Youde, who posted the howto as a bug on the
Ubuntu Laundpad bug page.