Comment 0 for bug 1575391

On Ubuntu MATE 16.04 one can select 4 compositing modes via MATE Tweak (german translation):
1. Marco (kein Komposit)
2. Marco (Programmkomposit)
3. Marco (Compton GPU-Komposit)
4. Compiz (anspruchsvolle Schreibtischeffekte mit GPU-Beschleunigung)

On my PowerMac G5 7,3 with a Radeon 9650 Pro only the 1st one works properly. The 2nd one works, but more sluggish and a jerkier mouse pointer. 3 and 4 trash the desktop showing wrong colours. Only VERY jerky mouse movement is possible then. The desktop is no longer in a usable state any longer, you can't click on anything. Restarting the desktop with "systemctl restart lightdm" from console returns the desktop usable (defaulting to 1st compositor.
Same problem on my PowerBook 5,6.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: xorg 1:7.7+13ubuntu3
ProcVersionSignature: Ubuntu 4.4.0-21.37-powerpc64-smp 4.4.6
Uname: Linux 4.4.0-21-powerpc64-smp ppc64
ApportVersion: 2.20.1-0ubuntu2
Architecture: powerpc
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: None
Date: Tue Apr 26 23:40:25 2016
DistUpgraded: Fresh install
DistroCodename: xenial
DistroVariant: ubuntu
ExtraDebuggingInterest: Yes, including running git bisection searches
GraphicsCard:
 Advanced Micro Devices, Inc. [AMD/ATI] RV350 [Radeon 9550/9600/X1050 Series] [1002:4150] (prog-if 00 [VGA controller])
   Subsystem: Advanced Micro Devices, Inc. [AMD/ATI] RV350 [Radeon 9550/9600/X1050 Series] [1002:4150]
InstallationDate: Installed on 2016-03-26 (31 days ago)
InstallationMedia: Ubuntu-MATE 16.04 LTS "Xenial Xerus" - Beta powerpc (20160326)
ProcEnviron:
 LANGUAGE=de_AT:de
 TERM=xterm
 PATH=(custom, no user)
 LANG=de_AT.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: root=UUID=d6fab932-3e79-4f5c-a392-c86c01b5a8f9 ro rootflags=subvol=@ radeon.agpmode=-1
SourcePackage: xorg
UpgradeStatus: No upgrade log present (probably fresh install)
version.compiz: compiz 1:0.9.12.2+16.04.20160415-0ubuntu1
version.libdrm2: libdrm2 2.4.67-1
version.libgl1-mesa-dri: libgl1-mesa-dri 11.2.0-1ubuntu2
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 11.2.0-1ubuntu2
version.xserver-xorg-core: xserver-xorg-core 2:1.18.3-1ubuntu2
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.10.1-1ubuntu2
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.7.0-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel N/A
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.12-1build2
xserver.bootTime: Tue Apr 26 22:55:40 2016
xserver.configfile: /etc/X11/xorg.conf
xserver.devices:
 input Logitech G100s Optical Gaming Mouse MOUSE, id 6
 input HID 046a:010d KEYBOARD, id 7
 input HID 046a:010d KEYBOARD, id 8
 input PMU KEYBOARD, id 9
xserver.errors:

xserver.logfile: /var/log/Xorg.0.log
xserver.version: 2:1.18.3-1ubuntu2
xserver.video_driver: radeon