Caused problems on Thinkpad X200s with Ubuntu Lucid
I'm running 64-bit Lucid on a Thinkpad X200s. When at "home base" this in a dual head configuration: X200 UltraBase/DisplayPort-to-DVI-D adapter/Dell 20-inch 1600x1200 panel. I tried the enable_fbc and lvds_downclock options.
enable_fbc does not seem to be supported by the i915 version in Lucid:
and adding it to /etc/modprobe.d/foo.conf options led to the module not loading, which in turn broke both displays: wrong resolution on both plymouth and gdm. In fact I could not see gdm. Not sure if it was not there at all or "displayed" with an offset that made it not visible on the screen.
Enabling only lvds_downclock still resuts in major problems with my system: Again, plymouth looks wrong (including barely visible cryptsetup prompt) and gdm is not shown. Furthermore, now attempting to ctrl-alt-F1 to get to a console results in a corrupt "rainbow" pattern on the bottom left of both screens, or just the laptop panel if the machine is booted with the Dell display switched off, instead of the console.