colors get screwed after resuming from S3
I have a Dell latitude D800 with a GeForce FX 5200 GPU. I run Ubuntu Gutsy 7.10 on it and all is well. Except for one thing : When I boot and watch a video (with Xv output) or TV through MythTV (laptop acts as a frontend), everything is fine. If I now put the laptop to sleep (using s2ram -f -s) and wake the laptop, everything is fine as well, I can watch videos or TV ... but after about 15mn, colors are suddenly degraded. It is mostly visible in darks areas. When I press a key, it gets even worse. The way to get back to normal is to do a quick vt switch (e.g. Alt+F2 -> Alt+F7). But it will be fine for only 15mn before it starts again. Rebooting elminates the problem until I put the laptop to sleep again.
I don't know where to start debugging that thing. Is it X or the nvidia driver ? I am using driver 100.14.19 prepackaged by ubuntu.