Public bug reported: My system has a Radeon HD 7750 and Radeon HD 6450, together driving 4 displays: Left: VGA on 7750 via DisplayPort adaptor, 1280x1024 Middle: DVI on 7750, 1920x1080 Right: HDMI on 7750, 1680x1050 Top (above Middle): VGA on 6450, 1280x1024
With only Left, Middle and Right enabled, everything works fine. When I try to enable the top display by running: $ xrandr --output VGA-1-0 --above DVI-0 --mode 1280x1024 then the top screen only displays noise, and the entire system will lock up for about 10 seconds at a time, then run again for 10 seconds (and the top screen goes blank), then lock up again, repeating until the top screen is disabled again. syslog and kern.log report one of the GPUs is locking up. With the proprietary driver fglrx, I can run all 4 displays, but it requires the use of Xinerama, so I have no RandR or compositing, which stinks. With the open source driver RandR and compositing work fine. ProblemType: Bug DistroRelease: Ubuntu 13.10 Package: xserver-xorg-video-ati 1:7.2.0-0ubuntu10 ProcVersionSignature: Ubuntu 3.11.0-12.19-generic 3.11.3 Uname: Linux 3.11.0-12-generic x86_64 ApportVersion: 2.12.5-0ubuntu2 Architecture: amd64 Date: Tue Oct 22 12:59:19 2013 InstallationDate: Installed on 2013-10-22 (0 days ago) InstallationMedia: Lubuntu 13.10 "Saucy Salamander" - Release amd64 (20131016.1) MarkForUpload: True SourcePackage: xserver-xorg-video-ati UpgradeStatus: No upgrade log present (probably fresh install) ** Affects: xserver-xorg-video-ati (Ubuntu) Importance: Undecided Status: New ** Tags: amd64 apport-bug saucy -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1243311 Title: GPU lockup when using 2 video cards To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-ati/+bug/1243311/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs