Comment 43 for bug 545096

I was able to reproduce that bug with -21 kernel but it seems a lot less frequent. So, to summarize, this is what happens:

There are four possible situations :
1) Everything is smooth and fine.
2) Splash screen is ugly but everything is fine once logged (not a real problem)
3) Normal session with backlight flickering. This starts immediatly at login and appears randomly during the whole session. This is a bit annoying but a bit subtle and you can work with it the whole day (if you are in a bright room. A bit more annoying in darker places).
4) Pink world. Heavy corruptions with freezes. This is appears randomly during the session but starts only after at least 4 or 5 minutes. This make it impossible to work with the computer but also impossible to know if you will hit the bug or not..

It has to be noted that those 4 situations are mutually exclusives. It means that if I have an ugly splash screen, I'm sure I will not have any corruption. Also, as soon as I see backlight flickering, I know I will not have any Pink World !

* With normal boot (-21 kernel) :
  - 50% of the time, everything is fine and smooth (1)
 - 40% of the time, backlight flickering (3)
 - 10% of the time, pink world (4)

* With normal boot (-20 kernel) :
  - 80% of the time, pink world (4)
  - 20% of the time, (3)

* With nomodeset (any known kernel):
 - 100% of the time, everything work but splashscreen (2)