@Christopher: I still have this crash with the upstream kernel version 3.12.0-031200. It seems that it still crash in 'r600_pcie_gart_tlb_flush'.
Note that I no longer have this crash if I remove this line from /etc/init/lightdm.conf (please have a look to the comment #7 for more details about that): echo OFF > /sys/kernel/debug/vgaswitcheroo/switch But then, my ATI/AMD GPU is still enabled and consume a lot of resources... ** Tags removed: needs-upstream-testing ** Tags added: kernel-bug-exists-upstream-v3.12 ** Changed in: linux (Ubuntu) Status: Incomplete => Confirmed -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1170917 Title: IP: [<ffffffffa01b6c05>] r600_pcie_gart_tlb_flush+0xf5/0x110 [radeon]; RIP: 0010:[<ffffffffa01b6c05>] [<ffffffffa01b6c05>] r600_pcie_gart_tlb_flush+0xf5/0x110 [radeon] To manage notifications about this bug go to: https://bugs.launchpad.net/linux/+bug/1170917/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs