After do-release-upgrade to 14.04, unity has video problems: The right-hand one inch of the screen is blank, and after 15 seconds the monitor goes into power-save-mode (i.e., it's blank). The computer is still running; I recover from this by using Ctrl-Alt-F1 to go to a virtual terminal, where I log in and then kill the gnome-session process. This takes me back to a login screen, where I can start up an Fvwm session, where all is well.

I should stress that Fvwm runs fine, which tells me that the video drivers are still fine. I actually spend all my time in Fvwm, and only start up unity on the rare occasions that I have to access something not available via Fvwm, but it would be good to be able to run unity when I need it.

I've tried many suggestions I found on the web, including totally reinstalling unity. I've run

rm -rf .conf/dconf
rm -rf .conf/.compiz-1
rm -rf .conf/gnome-disk-utility
rm -rf .conf/gnome-session
dconf reset -f /org/compiz
unity-tweak-tool --reset-unity
unity --reset-icons &disown
apt-get install --reinstall gnome-session

I purged every package with the word "unity" in the name, and then reinstalled all of them, including having to install and run ccsm to get unity to be among the sessions offered by the login screen. I have a complete list of what was purged, reinstalled, and installed, but it's about 390 lines, so I'm not including it here.

To repeat the main problem: It's acting as if unity is switching to some modeline that the monitor doesn't like (for those of us old enough to remember when we had to come up with modelines that suited our monitors and video cards before we could run X), and so the monitor is protecting itself by going into powersave mode. It's a flatscreen non-CRT monitor, so I don't even know if monitors still do that any more, but that's what it seems like.

If anyone knows what's happening, I'd very much appreciate hearing about it.

  • As a work-around, you could use an Xnest instance to run unity in a window while you're in FVWM... for example: Xnest:1 -ac & followed by DISPLAY=:1 unity – Stephen Dec 7 '16 at 0:08
  • @Stephen Thanks, lovely idea, but: when I try to give the unity command, I get a segmentation fault and unity exits. Any idea how to fix that? – Phil Hirschhorn Dec 7 '16 at 5:13
  • Ah ha! So unity explodes. That explains the symptoms, but sadly, I have no idea what the cause might be. ulimit -c unlimited, run it again, and then submit the resulting core file in a bug report? – Stephen Dec 7 '16 at 13:24
  • @Stephen Thanks much; I do appreciate the attempt. – Phil Hirschhorn Dec 8 '16 at 3:46
  • You could also use gdb on the core file and see why it's crashing, maybe it's something simple like a missing dependency... gdb ./core followed by where I think. – Stephen Dec 8 '16 at 13:45

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