Radeon9000 pro on PPC, Xorg-7.1.1: flickering red channel

[Giuliano Pochini]

I already searched in the archives and this seems a new issue.

I've just upgraded from Xorg-6.8.2 (Gentoo 2005.1) to 

I'm using Xorg-7.1.1 with xf86-video-ati-6.6.3. Pixels have a flickering red
channel. The pixels which are affected are those with the red channed
between 0 and R (R is about 128). The way it flickers and the value of R
change each time I start X or I switch from a console to X. The interesting
part is that if I launch xvidtune and I click "apply" without changing
anything or I change the mideo mode with ctrl-alt-+/-, it fixes the problem.
As soon as I switch to a console and back to X, the noise reappears. I
played with several xorg settings (resolution, bpp, dri), but it makes no
difference. Any clue ?

$ uname -a
Linux Jay 2.6.20 #1 SMP Mon Feb 5 22:42:18 CET 2007 ppc 7455, altivec supported PowerMac3,6 GNU/Linux
$ /sbin/lspci | grep Radeon
0000:00:10.0 VGA compatible controller: ATI Technologies Inc Radeon RV250 If [Radeon 9000] (rev 01)


--
Giuliano.