I just installed a 86c325 virge as a secondary graphics card. Using xorg-6.8.2, (I just realised I'm cheating a tiny bit because I'm not actually running Debian on this box).
At a depth of 24 and 1024x768 resolution I noticed significant flicker when the screen was redrawn. For example putting two terminals on the screen didn't cause any problems as the image was stable. However I saw flicker every time I sent a new line and changed the text, the flicker was across the entire screen. Loading ltris caused it to flicker constanty, presumably due to ltris repainting itself. As was said earlier the problem appeared to be related to the horizontal line as it would flicker roughly two cm right of painted pixels, random flickers but in a consistant location. I tried lowering the resolution and following the suggestions above I tried lowering the color depth to 16. Both of those solutions caused the screen to behave perfectly. Now I just have to decide which I prefer. -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]