Bug#668828: I experience same bug. Possible workarounds found.
Blank or corruption across bottom half of display using nouveau. Same as in pics attached by original report. Problem does not appear when using FBDEV or NV video drivers.
The behavior and workarounds repeat in:
Debian7 Gnome Classic, MintPPC11 LXDE
Hardware: Apple PowerMac G5 PPC NVIDIA GeFroce FX 5200 Ultra (AGP 8X Pro) Dell VGA flat panel Monitor via DVI -- everymac.com link: http://www.everymac.com/systems/apple/powermac_g5/specs/powermac_g5_1.6.html
I have found three possible workarounds. (One mentioned earlier by Jeroen D.)
WORKAROUND 1: (no xorg.conf)
Disable hardware acceleration/rendering (3d support) by:
a. append nouveau.noaccel=1 to yaboot command
b. edit /etc/modprobe.d/nouveau.conf to include
options nouveau noaccel=1
Major downside to workaround 1 is it breaks video playback. (DVD, Minituve, Flashvideoreplacer.)
WORKAROUND 2: (no xorg.conf)
Change display mode using xrandr and then change it back. I.E. I am using DVI-I-2 at 1280x1024:
xrandr --output DVI-I-2 --mode 1024x768 --panning 1024x768
xrandr --output DVI-I-2 --mode 1280x1024 --panning 1280x1024
This resolves the issue. No idea why the --panning option seems to have affect.
Create xorg.conf that disables disconnected outputs (so xrandr -q shows only one output instead of connected plus two disconnected) AND add "Virtual" entry under display subsection that is square. xorg.conf attached.
If Virtual is set to actual display size (1280 1024), no change in display corruption. When set to square of my H size (1280 1280), display corruption is not there.
Speculation: Problem is related to video memory utilized by "off screen" elements.
1. reportbug output with no xorg.conf and problem occurring
2. reportbug output with xorg.conf that resolves
3. xorg.conf that does NOT resolve
4. xorg.conf that does resolve. (Only difference between the two xorg.conf is the "Virtual" entry.
My first bug communication. Let me know if I can improve.
Description: GNU Zip compressed data