Comment 16 for bug 684992

Forwarding this bug from Ubuntu reporter Jay Taoko:
http://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-ati/+bug/715405

[Problem]
Rendering corruption is seen in tooltips (see screenshots). This was reported by a user and reproduced by Jay who is one of the Unity/Compiz developers.

[Original Description]
Some lines appears above the tooltip when running Unity on an ATI gpu with the open source driver. It does not happen with other GPU. The problem is random and shows up on a few of the tooltips only.
To reproduce, move the mouse over the launcher icons (to bring up the tooltips) for a little while. It is best if you have many icons in the launcher. Shortly after, some tooltips will exhibit the problem.

DistroRelease: Ubuntu 11.04
Package: xserver-xorg-video-ati 1:6.13.2+git20110124.fadee040-0ubuntu4
ProcVersionSignature: Ubuntu 2.6.38-2.29-generic-pae 2.6.38-rc3
Uname: Linux 2.6.38-2-generic-pae i686
Architecture: i386
CompositorRunning: compiz
DRM.card0.DIN.1:
 status: disconnected
 enabled: disabled
 dpms: On
 modes:
 edid-base64:
Date: Tue Feb 8 15:39:11 2011
DistUpgraded: Yes, recently upgraded Log time: 2011-01-28 11:00:32.139757
DistroCodename: natty
DistroVariant: ubuntu
GraphicsCard: Subsystem: PC Partner Limited Radeon HD 4670 512MB DDR3 [174b:e880]
InstallationMedia: Ubuntu 10.10 "Maverick Meerkat" - Release i386 (20101007)
MachineType: System manufacturer System Product Name
ProcEnviron:
 LANGUAGE=en_CA:en
 LANG=en_CA.UTF-8
 LC_MESSAGES=en_CA.utf8ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.38-2-generic-pae root=UUID=96c603fd-a46b-4516-ac34-28d1de74227b ro quiet splash vt.handoff=7
SourcePackage: xserver-xorg-video-ati
dmi.bios.date: 11/18/2010
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 0701
dmi.board.asset.tag: To be filled by O.E.M.
dmi.board.name: P8P67 PRO
dmi.board.vendor: ASUSTeK Computer INC.
dmi.board.version: Rev 1.xx
dmi.chassis.asset.tag: Asset-1234567890
dmi.chassis.type: 3
dmi.chassis.vendor: Chassis Manufacture
dmi.chassis.version: Chassis Version
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr0701:bd11/18/2010:svnSystemmanufacturer:pnSystemProductName:pvrSystemVersion:rvnASUSTeKComputerINC.:rnP8P67PRO:rvrRev1.xx:cvnChassisManufacture:ct3:cvrChassisVersion:
dmi.product.name: System Product Name
dmi.product.version: System Version
dmi.sys.vendor: System manufacturer
version.compiz: compiz 1:0.9.2.1+glibmainloop4-0ubuntu9
version.libdrm2: libdrm2 2.4.23-1ubuntu3
version.libgl1-mesa-glx: libgl1-mesa-glx 7.10-1ubuntu1
version.xserver-xorg: xserver-xorg 1:7.6~3ubuntu3
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:6.13.2+git20110124.fadee040-0ubuntu4
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.14.0-1ubuntu6
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:0.0.16+git20110107+b795ca6e-0ubuntu4