I'm using Ubuntu 12.04 (upgraded from 11.10), everything seemed to work fine until today when my laptop monitor suddenly stopped working. Here are the facts:

My laptop is a Dell Latitude E6410, Intel graphics.
External Monitor is attached through a docking station.
Everything worked fine for about 6-7 month, then upgraded to 12.04
Issue started today after a week of upgrade.

I think the issue started after I ran CounterStrike 1.6, both monitors blinked and then only the attached monitor which is connected to a docking station continued to work I thought at first that was a transient issue but then I've rebooted, removed the battery but the same happens.

Laptop Monitor and external monitor work fine up to login screen, but after I login it goes black

Whenever I try to re-enable laptop monitor from Display Manager I get errors:

The selected configuration for displays could not be applied 
could not set the configuration for CRTC 63

Not sure what technical details are required but here are some:

$ xrandr
Screen 0: minimum 320 x 200, current 3120 x 1050, maximum 8192 x 8192
eDP1 connected (normal left inverted right x axis y axis)
  1440x900       60.0 +   40.0  
VGA1 disconnected (normal left inverted right x axis y axis)
HDMI1 connected 1680x1050+0+0 (normal left inverted right x axis y axis) 474mm x 296mm
  1680x1050      60.0*+
   1280x1024      75.0     60.0  
   1152x864       75.0  
   1024x768       75.1     60.0  
   800x600        75.0     60.3  
   640x480        75.0     60.0  
   720x400        70.1  
DP1 disconnected (normal left inverted right x axis y axis)
HDMI2 disconnected (normal left inverted right x axis y axis)
DP2 disconnected (normal left inverted right x axis y axis)

$ tail /var/log/Xorg.0.log
[  8367.132] (WW) intel(0): flip queue failed: Device or resource busy
[  8367.132] (WW) intel(0): Page flip failed: Device or resource busy
[  8367.174] (WW) intel(0): flip queue failed: Device or resource busy
[  8367.174] (WW) intel(0): Page flip failed: Device or resource busy
[  8367.174] (WW) intel(0): flip queue failed: Device or resource busy
[  8367.174] (WW) intel(0): Page flip failed: Device or resource busy
[  8367.265] (WW) intel(0): flip queue failed: Device or resource busy
[  8367.265] (WW) intel(0): Page flip failed: Device or resource busy
[  8367.265] (WW) intel(0): flip queue failed: Device or resource busy
[  8367.265] (WW) intel(0): Page flip failed: Device or resource busy

I'm using gnome-shell, and the only ways I've been able to get both display working have been:

1) Booting with laptop disconnected from docking and then re attach external with VGA instead of DVI, but only worked for a session.

2) Removing xserver-xorg-video-intel, but then I gnome-shell is gone as well as dri

I would appreciate any suggestions.

Regards,

============================= WORKAROUND FOUND =============================

So I have tried few things and here is what worked:

I've installed a newer version of xserver-xorg-video-intel (2.19 vs 2.17) from ppa:xorg-edgers/ppa, it didn't work at first, it was only showing low graphics mode, so I tried with a different linux-image 3.0.0-19-generic-pae instead of 3.2.0-24-generic-pae, which I believe is 12.04 precise default, then everything started to work again, Now I've installed 3.4.0-1-generic-pae from same ppa and everything goes flawless so I believe the issue is either with linux-image 3.0.0-19-generic-pae or xserver-xorg-video-intel 2.17.

Hope this helps someone in the future.

PS: Now xrandr shows multiple modes for my laptop monitor

$ xrandr
Screen 0: minimum 320 x 200, current 3120 x 1050, maximum 8192 x 8192
eDP1 connected 1440x900+1680+0 (normal left inverted right x axis y axis) 303mm x 189mm
   1440x900       60.0*+   59.9     40.0  
   1360x768       59.8     60.0  
   1152x864       60.0  
   1024x768       60.0  
   800x600        60.3     56.2  
   640x480        59.9  
VGA1 disconnected (normal left inverted right x axis y axis)
HDMI1 connected 1680x1050+0+0 (normal left inverted right x axis y axis) 474mm x 296mm
   1680x1050      60.0*+
   1280x1024      75.0     60.0  
   1152x864       75.0  
   1024x768       75.1     60.0  
   800x600        75.0     60.3  
   640x480        75.0     60.0  
   720x400        70.1  
DP1 disconnected (normal left inverted right x axis y axis)
HDMI2 disconnected (normal left inverted right x axis y axis)
DP2 disconnected (normal left inverted right x axis y axis)