Looks like you have run into the infamous CPU frequency issue. http://www.thinkwiki.org/wiki/Problem_with_CPU_frequency_scaling
Solution is to make sure you are running with high quality AC power. Workaround is to edit /etc/default/grub Find the following line and add processor.ignore_ppc=1 so it looks like this: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash processor.ignore_ppc=1" then sudo update-grub && sudo reboot. Have a nice day. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1246793 Title: Battery charging slows down laptop Status in “linux” package in Ubuntu: Incomplete Bug description: Following up on Bug #962712 which was marked as invalid, instead of fixed (gee, thanks...) I'm using Ubuntu 13.10 and this still happening pretty badly. Steps to reproduce: 1) Unplug laptop, plug-in second monitor, drain battery until OS warns user and asks her to plugin laptop 2) Plugin laptop Expected: Laptop works normally Actual: Laptop slows down severely. -=-=- Drilling down, run `cpufreq-info` Expected: driver: acpi-cpufreq [...] current policy: frequency should be within 800 MHz and 2.80 GHz. Actual: driver: acpi-cpufreq [...] current policy: frequency should be within 800 MHz and 800 MHz -=-=- Drilling down, this is known, lingering problem, and is not "invalid", please triage instead of sweeping under the rug * http://ubuntuforums.org/showthread.php?t=1921292 * http://askubuntu.com/questions/186387/laptop-slows-down-while-charging-battery * http://bit.ly/17vgUO0 * ... -=-=- Thank you for your consideration. --- ApportVersion: 2.12.5-0ubuntu2.1 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: dac514 2414 F.... pulseaudio DistroRelease: Ubuntu 13.10 EcryptfsInUse: Yes HibernationDevice: RESUME=UUID=b95f5ff9-5665-42f8-8b10-f2ae3ca2411f InstallationDate: Installed on 2012-06-12 (505 days ago) InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425) MachineType: LENOVO 4286CTO MarkForUpload: True Package: linux (not installed) ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.11.0-12-generic root=UUID=59641606-e542-4c74-8a31-08c66bfae100 ro quiet splash vt.handoff=7 ProcVersionSignature: Ubuntu 3.11.0-12.19-generic 3.11.3 RelatedPackageVersions: linux-restricted-modules-3.11.0-12-generic N/A linux-backports-modules-3.11.0-12-generic N/A linux-firmware 1.116 RfKill: 0: phy0: Wireless LAN Soft blocked: no Hard blocked: no Tags: saucy Uname: Linux 3.11.0-12-generic x86_64 UpgradeStatus: Upgraded to saucy on 2013-10-08 (23 days ago) UserGroups: adm audio cdrom dip lpadmin plugdev sambashare sudo WifiSyslog: dmi.bios.date: 07/18/2013 dmi.bios.vendor: LENOVO dmi.bios.version: 8DET69WW (1.39 ) dmi.board.asset.tag: Not Available dmi.board.name: 4286CTO dmi.board.vendor: LENOVO dmi.board.version: Not Available dmi.chassis.asset.tag: No Asset Information dmi.chassis.type: 10 dmi.chassis.vendor: LENOVO dmi.chassis.version: Not Available dmi.modalias: dmi:bvnLENOVO:bvr8DET69WW(1.39):bd07/18/2013:svnLENOVO:pn4286CTO:pvrThinkPadX220:rvnLENOVO:rn4286CTO:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable: dmi.product.name: 4286CTO dmi.product.version: ThinkPad X220 dmi.sys.vendor: LENOVO To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1246793/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
