Thank you again.
Yes, you are right. Vesa is a generic graphics driver and not optimised for my card therefore DRI uncapable.
I cound solve this problem by reducing the resolution.
I found the solution for the display corruption from the web site (http://www.winischhofer.eu/linuxsispart1.shtml#12
) you offered me. It says:
And please don't complain about "driver bugs" if you see "flashing lines" (display corruption) on the screen; these are the typical effects of a bandwidth problem and unavoidable - even the Windows driver can't do better. In such cases, reduce the resolution and/or refresh rate and/or color depth, or use one output (CRT1 or CRT2) only.
OMG!! My SiS761 chipset was DAMN SLOW!!! That's where the problem is!
It seems to be IMPOSSIBLE to enable DRI on my computer according to this article.
I should have buy one with a dedicated local framebuffer memory!
P.S. How did you find this web site? I'ts totally incredible if you found it easily.