problem with vesa driver in 7.1.1

[starcycle at gmail.com]

hi, i use arch linux, which recently upgraded X to 7.1.1. the Xorg mga
driver doesn't work with my G450 through DVI, so until i get the
matrox driver installed i always revert to using vesa.

7.0.0 worked fine with vesa, but with 7.1.1 there is a very slow
window redraw that takes massive cpu cycles. for example, to move a
simple terminal window across the screen takes 90% cpu, and the
terminal "redraws" in the new location from top to bottom very slowly.
scrolling web pages is the same. by comparison, with a working vesa/X
7.0.0 setup, moving the window across the screen takes about 2-5% cpu,
and there is no visible "redrawing," everything is smooth and normal.

with kernel 2.6.17.13, X fails while starting and gives these errors:

-------------
(EE) VESA(0): Set VBE Mode Failed!

Fatal Server Error:
AddScreen/ScreenInit failed for driver 0
--------------

with kernel 2.6.16.x, X/vesa only works with 7.0.0. i haven't tested
any of the kernels in between the last 2.6.16.x (2.6.16.28, which i'm
using now) and 2.6.17.13.

you can compare a working with a non-working Xorg.0.log here:

http://datalink.homelinux.com/~jeff/files/Xorg.0.log-working
http://datalink.homelinux.com/~jeff/files/Xorg.0.log-nonworking

i don't know what most of that is, but some differences i did notice
are that the working version loads "LBX":

(II) Initializing built-in extension LBX

while 7.1.1 does not, and the way they pre-init and probe the resource
ranges looks different.

maybe something's also wrong with my configuration
(http://datalink.homelinux.com/~jeff/files/xorg.conf), but it's worked
fine up until 7.1.1.

cheers,
s.c.