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
proprietary matrox driver installed i always just revert to using
vesa.

7.0.0 works 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 very slowly. scrolling web pages is the
same: takes a lot of cpu, and has to "redraw" each time you scroll
down. iow, it's basically unusable. by comparison, with a working
vesa/X 7.0.0 setup, moving a 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 properly 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 the log of a working X (7.0.0) with a non-working X
(7.1.1) 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 the log 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 and is working now with 7.0.0. i hope any of this
is useful.

cheers,
s.c.