I started experiencing this hang after I upgraded from Kubuntu 13.04 to 13.10 yesterday (both 64 bit).
The freeze usually happens when I try to context switch between windows running Firefox or between Firefox/Thunderbird windows. It also happens when I close windows. The problem is not consistent (i.e., happening on every switch/close) but happens fairly frequently. Ctl-Alt-F1/Ctl- Alt-F7 does not always help. Recovery takes several seconds. A reboot does not fix the problem, i.e., hangs happen after reboots. Kernel 3.11.0-12-generic #19-Ubuntu $ lsmod | grep nouveau nouveau 943295 2 mxm_wmi 13021 1 nouveau wmi 19070 2 mxm_wmi,nouveau video 19318 1 nouveau i2c_algo_bit 13413 1 nouveau ttm 83995 1 nouveau drm_kms_helper 52651 1 nouveau drm 296739 4 ttm,drm_kms_helper,nouveau libdrm-nouveau2:amd64 2.4.46-1 libdrm-nouveau2:i386 2.4.46-1 xserver-xorg-video-nouveau 1:1.0.9-2ubuntu1 libc6:amd64 2.17-93ubuntu4 libc6:i386 2.17-93ubuntu4 KDE: 4.11.2 CPU: vendor_id : AuthenticAMD cpu family : 15 model : 75 model name : AMD Athlon(tm) 64 X2 Dual Core Processor 4200+ stepping : 2 cpu MHz : 2204.597 cache size : 512 KB Memory: 2GB -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1184451 Title: Ubuntu 13.10 random screen freeze while Normal OS activites To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xorg-server/+bug/1184451/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
