Bug#525619: xserver-xorg-video-intel: screen blank after returning to vt7

[Sanjoy Mahajan <sanjoy@MIT.EDU>]

>> In both cases, the backlight was still on, but the screen was blank.
>> And switching back to vt1 or any other non-X vt, then back to vt7,
>> did not solve it.  However, putting the laptop into S3 sleep and then
>> resuming solved the problem.

> can you still reproduce this with latest intel driver and kernel (with
> kernel mode setting)?

I see a similar, perhaps identical problem.

Twice now (today and a few days ago), the laptop has woken up with the
screen almost completely black.  I can barely see the windows, but the
laptop is otherwise fine; for example, I can edit in Emacs if I could do
it all without reading the characters.  Cycling S3 sleep doesn't restore
the brightness, nor does restarting xdm and the X server -- I need to
reboot and then the screen is back to normal brightness.

This is with xserver-xorg-video-intel 2.9.1-3 and kernel 2.6.33 (vanilla).
I imagine that it has KMS -- I didn't do anything special to disable
that when I compiled the kernel.