Comment 69 for bug 595555

Created attachment 460189
Proof-of-concept patch to fix this issue based on Comment #49.

Re: Comment #55, Comment #54, Comment #53, Comment #50
Me too, observed this issue on F14 with 80-90% occurence, about the
same frequency as in F13.

Here is a proof-of-concept patch, based on my Comment #49. Anyone
interested please try it out and see how it goes for you. Thanks.
When I tried it, I was able to break the gamma fading all the time.
As a prototype patch, I also added a flag file
"/tmp/disable.bug612620.fix" so you can enable/disable the proposed
fix on the fly.

Adam,
Chris,
If you don't mind, would you please review the proposed patch?
Thanks.