Perhaps slightly off-topic but maybe someone else here has experienced this problem.
I'm running PMC on an 13" white macbook with Ubuntu 12.10. I have the DVI output of the macbook connected to one of the hdmi inputs on my Yamaha decoder. This works fine up until I turn off the decoder, something in ubuntu seems to detect this and react to it in some way. Unfortunately ubuntu doesn't seem to detect when the decoder is turned on again, leaving me with a black screen on the tv, and a black screen with a white mouse pointer on the laptop itself.
If I disconnect and reconnect the hdmi cable completely this seems to trigger other behaviour, doing this usually corrects the issue. Another workaround seems to be resetting the outputs with xrandr (although I've not had 100% success rate).
Is there some config file / script I can tweak to disable the detection that decoder gets turned off?
I had this same issue last month. I was able to determine from the Mac system log that the problem was when the receiver was turned off, the Mac would see that the connected display (the AV receiver via the HDMI cable) was disconnected. The Plex client doesn't handle it well when its display goes away. In your case, it was just a black screen. In my case, the app would crash.
Are you running the laptop screen mirrored to the DVI output (both displays showing Plex) or are you running it in 2 display mode (Linux on the laptop screen, Plex running full screen on the DVI output)?
I'm guessing that you are in 2 display mode so when you turn off the receiver and the display goes away, Plex doesn't know where to send its output. When you turn the receiver back on, Plex is not informed by the laptop of the display change so you are left with the black screen.
Before turning off the receiver, try switching from full screen to windowed mode. When the display goes away, the window should appear on the laptop screen.
When you want to watch Plex, turn on the receiver then switch Plex back into full screen mode.
Hope this helps. Probably not the answer you are looking for but now you know what is going on and can figure out a work-around.
I have been looking all over for a way to force the screen output but so far I've had no luck with this either. I'll try to remember this topic if I ever get around to solving the issue.
