To the best of my knowledge, this specific (resume from suspend, intel_pstate, performance mode) issue has been fixed in the upstream kernel. However, I never understood this issue to be specific to battery mode, an interesting twist.
Note that there are other issues, and sometimes it is hard to separate the issues and they tend to cross contaminate these bug reports. See also: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1484587/comments/5 -- 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/1497520 Title: Slow performance after resuming from/on battery (CPUs do not scale above 800MHz) Status in linux package in Ubuntu: Confirmed Bug description: I have noticed slow performance after resuming from STR on battery. I can not trigger this always, but it seems to be related to suspending and resuming while on battery. The CPU scaling governors look like this then: % cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor powersave performance performance performance % cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_driver intel_pstate intel_pstate intel_pstate intel_pstate % cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_max_freq 3200000 3200000 3200000 3200000 When watching the current CPU frequencies, it can be seen that they don't go above 800000 ('watch grep \"cpu MHz\" /proc/cpuinfo'). I cannot see why they are limited to 800000. It looks like https://bugzilla.kernel.org/show_bug.cgi?id=61241, but /sys/devices/system/cpu/intel_pstate/max_perf_pct is at 100. Just writing the same setting for cpu0 again fixes it, and all CPUs will be scaled above 800MHz again: % echo powersave | sudo tee /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor ProblemType: Bug DistroRelease: Ubuntu 15.04 Package: linux-image-3.19.0-28-generic 3.19.0-28.30 ProcVersionSignature: Ubuntu 3.19.0-28.30-generic 3.19.8-ckt5 Uname: Linux 3.19.0-28-generic x86_64 ApportVersion: 2.17.2-0ubuntu1.4 Architecture: amd64 CurrentDesktop: Unity Date: Sat Sep 19 10:39:02 2015 HibernationDevice: RESUME=UUID=d39463f5-889e-42ba-a729-f3f442f0c8dd InstallationDate: Installed on 2012-05-28 (1208 days ago) InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425) MachineType: LENOVO 42992PG ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.19.0-28-generic root=/dev/mapper/vg0-rootlv ro quiet splash RelatedPackageVersions: linux-restricted-modules-3.19.0-28-generic N/A linux-backports-modules-3.19.0-28-generic N/A linux-firmware 1.143.3 SourcePackage: linux UpgradeStatus: Upgraded to vivid on 2015-05-14 (127 days ago) dmi.bios.date: 05/14/2015 dmi.bios.vendor: LENOVO dmi.bios.version: 8DET70WW (1.40 ) dmi.board.asset.tag: Not Available dmi.board.name: 42992PG 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:bvr8DET70WW(1.40):bd05/14/2015:svnLENOVO:pn42992PG:pvrThinkPadX220Tablet:rvnLENOVO:rn42992PG:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable: dmi.product.name: 42992PG dmi.product.version: ThinkPad X220 Tablet dmi.sys.vendor: LENOVO To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1497520/+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