I am running XBMC (Frodo) on an Asus U47A laptop (Intel Sandybridge graphics) with Ubuntu 12.04. The laptop is connected to an older Phillips 27" tube HDTV via HDMI. What I would like is for XBMC to stay running, and appear when I turn on my TV. What actually happens is that when I turn off my TV, the HDMI signal stops and doesn't resume when the TV is turned back on. To re-enable the signal, I've got to open the laptop lid which re-enables the laptop screen, and I guess figures out that the TV is there and turns it on as well - but rearranges my windows, so XMBC isn't where it was. Alternately, I can unplug and replug the HDMI, but that's annoying too.
I know that the TV is older, but the functionality I expect worked fine when running XBMC on an old MacBook, so I know it can work.
I've tried for about a week so far, with no luck. Obviously I've tried setting the lid actions to 'nothing' in the settings. I've tried disabling the lid switch (as per here) hoping to keep Ubuntu from disabling the laptop monitor and rearranging everything - but no luck. Shutting the lid still reconfigures the monitors. I've tried various combinations of gconf, dconf and settings to force Ubuntu to keep the HDMI on. I've tried to disable DMPS (as per here) in hopes of preventing the sleep in the first place.
I've even logged the callbacks via these instructions to see if I can detect a signal when the TV is powered on. I do not get any callbacks when the TV goes off or on. I have had marginal success reactivating the TV after it's been powered on by sending the command
xset dmps force off, which blanks both screens, then when the mouse is moved or a key pressed the TV wakes. Sending
xset dmps force on does NOT wake up the TV - it has to go off and back on. However, those commands re-enables DMPS, which I've tried to turn off, so I don't think it's a solution either.
Another item of interest is that when I do the
xset dmps force off, a
xset -q shows "DMPS ON, Monitor ON". But when I do a
xset -dmps to turn it off, the -q shows "DMPS OFF" and doesn't mention the monitor state at all.
In the end, it would be nice if Ubuntu did NOT alter the HDMI signal at all - sending continuously. I would like to leave the laptop lid shut, and the HDMI signal to be going when I turn the TV on. I'm not a long-term Linux user, but I'm willing to try just about anything to get this to work!