Details:
1. Issue has been happening since 11.10, but same thing still happens in 12.04.
2. Hardware: HP EliteBook 8440p with Intel Graphics.
3. Only happens when the system is docked, otherwise there is no issue.
Steps to Reproduce:
1. Go to "Brightness and Lock".
2. Set the screen to turn off when inactive for 10 minutes (though timeframe doesn't seem to matter).
3. Set "Lock screen after:" to "Screen turns off".
4. Wait for the screen to dim and turn blank.
5. Wait longer for the screen to power off completely.
6. Wait another minute or so.
7, The external monitor will start to flicker on-and-off for a bit.
8. Try to unlock the screen.
9. The screen will successfully unlock.
10. Once unlocked you will see that your window manager (Compiz) has melted down. You cannot resize windows, etc. because the title bars have all disappeared.
11. I have found no way to recover from this issue short of a reboot (I usually get to a command terminal and try to shut it down as gracefully as I can).
The only work-around to this issue is to set "Turn screen off when inactive for:" to "Never". However, this is not ideal as it means the screen will always continue to suck battery even after the screen has been locked (even when not docked, unless I remember to change this setting every time I undock).
I am assuming I cannot be the only one having this issue.
I have confirmed this same issue happens when an external monitor is attached and I close the cover of the laptop (thus trying to suspend the laptop). I have attached an error image and also, here is part of the log (it gives very little inforamation):
[ 609.376] (II) PM Event received: Capability Changed
[ 609.376] I830PMEvent: Capability change
[ 609.890] (II) intel(0): EDID vendor "DEL", prod id 16404
[ 609.890] (II) intel(0): Using hsync ranges from config file
[ 609.890] (II) intel(0): Using vrefresh ranges from config file
[ 609.890] (II) intel(0): Printing DDC gathered Modelines:
[ 609.890] (II) intel(0): Modeline "1280x1024"x0.0 108.00 1280 1328 1440 1688 1024 1025 1028 1066 +hsync +vsync (64.0 kHz)
[ 609.890] (II) intel(0): Modeline "800x600"x0.0 40.00 800 840 968 1056 600 601 605 628 +hsync +vsync (37.9 kHz)
[ 609.890] (II) intel(0): Modeline "640x480"x0.0 31.50 640 656 720 840 480 481 484 500 -hsync -vsync (37.5 kHz)
[ 609.890] (II) intel(0): Modeline "640x480"x0.0 25.18 640 656 752 800 480 490 492 525 -hsync -vsync (31.5 kHz)
[ 609.890] (II) intel(0): Modeline "720x400"x0.0 28.32 720 738 846 900 400 412 414 449 -hsync +vsync (31.5 kHz)
[ 609.890] (II) intel(0): Modeline "1280x1024"x0.0 135.00 1280 1296 1440 1688 1024 1025 1028 1066 +hsync +vsync (80.0 kHz)
[ 609.890] (II) intel(0): Modeline "1024x768"x0.0 78.75 1024 1040 1136 1312 768 769 772 800 +hsync +vsync (60.0 kHz)
[ 609.890] (II) intel(0): Modeline "1024x768"x0.0 65.00 1024 1048 1184 1344 768 771 777 806 -hsync -vsync (48.4 kHz)
[ 609.890] (II) intel(0): Modeline "800x600"x0.0 49.50 800 816 896 1056 600 601 604 625 +hsync +vsync (46.9 kHz)
[ 609.890] (II) intel(0): Modeline "1152x864"x0.0 108.00 1152 1216 1344 1600 864 865 868 900 +hsync +vsync (67.5 kHz)
[ 610.525] (II) intel(0): Allocated new frame buffer 2880x1024 stride 11776, tiled
[ 611.309] (EE) intel(0): failed to set mode: Invalid argument