Lemur Ultra, 12.04: no HDMI device in sound settings

[shochatd]

I tried the HDMI output today on my new Lemur Ultra (I had not tried it before upgrading to 12.04). Picture was fine but no audio. I tried sound settings, but there was nothing obvious there to help. I found this addressed on the troubleshooting list on the System 76 support area, but it claimed that there would be a HDMI device listed under the output tab in sound settings. But I see no such devide -- only speakers and headphones. Is there some package I need to install? I did run the "restore" function in the System 76 Driver after upgrading.
-- David

[shochatd]

After a restart, I tried again and this time the HDMI device was there. So I selected it and it worked. No idea what caused the situation to change.

[brdmn]

I tried arandr -- available in the standard repository, and a useful alternative, especially if you're using a variant distro like Xubuntu. Among other things, it lets you "activate" HDMI. See http://www.ubuntugeek.com/arandr-a-s...or-xrandr.html

[jaychandran_s]

Even I was having the same problem. The best method(that worked for me) was to update the entire OS, and then Restart the computer. I know this sounds a little stupid, but it did work for me, and even now, sometimes when I get the same problem, I follow the same procedure.

Hope this Helps!!

[shochatd]

My current understanding is that while the video subsystem notices instantly when an HDMI device is connected or disconnected, the audio is not so smart. The OS has to be restarted to detect either transition. I think it's safe to consider this a bug, and I assume it will be fixed some time in the future.
-- David

[shochatd]

I guess it's time to write this up as a bug in launchpad, but I don't know what package it should be written against. Is it a kernel problem, an alsa problem, a pulse-audio problem, or something else? Again, I can get it to work, but only by restarting with the HDMI plugged in (which makes the HDMI show up in Sound Settings). Since the video subsystem obviously detects the HDMI immediately, the audio should as well.
-- David

[isantop]

I guess it's time to write this up as a bug in launchpad, but I don't know what package it should be written against. Is it a kernel problem, an alsa problem, a pulse-audio problem, or something else? Again, I can get it to work, but only by restarting with the HDMI plugged in (which makes the HDMI show up in Sound Settings). Since the video subsystem obviously detects the HDMI immediately, the audio should as well.
-- David

I would report it against the kernel. If that ends up being the wrong project, it will be marked against the correct project and marked invalid as a kernel bug.

[shochatd]

I just discovered a couple of things that may shed light on this problem: First, if I kill and then restart pulseaudio, that will make it "notice" the HDMI and it will then show up in sound settings. Still not a solution, but better than restarting the OS. The other thing is that if I monitor the output devices tab of pavucontrol during all this, there is only one device listed at a time, namely the one I have selected in sound settings. It seems to me that implies that the selection is done at a lower layer than Pulse Audio. But if that's the case, it's surprising that restarting PA forces the HDMI to be "noticed". When I use this method, I sometimes get an error dialog saying that "Ubuntu 12.04 has experienced an internal error" involving gnome-control-center, but things continue to work in spite of this.

[shochatd]

Slight correction to my last post, which may shed some light: I did another test today to confirm that the problem is still present: If I plug in the HDMI cable (with TV on at the other end), the video reconfigures immediately, but the HDMI does not show up in the Output tab of Sound Settings. So as before, I tried pulseaudio --kill. Immediately, I saw the HDMI added to the list of outputs, even before I restarted pulseaudio. So it isn't really restarting PA that makes the HDMI get "noticed", but rather it's the killing of PA that does it. To me, that puts a whole new slant on the problem. It's as if PA is interfering with the refreshing of the list of outputs, so when it is killed, that process can proceed. Does that imply that the bug/blame goes to Pulse Audio?

[isantop]

Slight correction to my last post, which may shed some light: I did another test today to confirm that the problem is still present: If I plug in the HDMI cable (with TV on at the other end), the video reconfigures immediately, but the HDMI does not show up in the Output tab of Sound Settings. So as before, I tried pulseaudio --kill. Immediately, I saw the HDMI added to the list of outputs, even before I restarted pulseaudio. So it isn't really restarting PA that makes the HDMI get "noticed", but rather it's the killing of PA that does it. To me, that puts a whole new slant on the problem. It's as if PA is interfering with the refreshing of the list of outputs, so when it is killed, that process can proceed. Does that imply that the bug/blame goes to Pulse Audio?

My guess is that this is related to the Intel Graphics issue. Try fixing that problem and see if that comes back.