kernel-packages team mailing list archive

[Joseph Salisbury <joseph.salisbury@xxxxxxxxxxxxx>]

Would it be possible for you to test the latest upstream kernel? Refer
to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest
v4.6 kernel[0].

If this bug is fixed in the mainline kernel, please add the following
tag 'kernel-fixed-upstream'.

If the mainline kernel does not fix this bug, please add the tag:
'kernel-bug-exists-upstream'.

Once testing of the upstream kernel is complete, please mark this bug as
"Confirmed".


Thanks in advance.

[0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.6-rc4-wily/


** Changed in: linux (Ubuntu)
   Importance: Undecided => Medium

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https://bugs.launchpad.net/bugs/1567316

Title:
  CPU maximum frequency goes down after every resume

Status in linux package in Ubuntu:
  Incomplete

Bug description:
  This bug applies to Ubuntu 15.10, kernel 4.2.0-35-generic and at least
  two before that.

  A while ago I noticed that my system had become unbearably slow. A reboot fixed it for a while.
  It turns out that the problem is related to resuming after closing the laptop lid. After every resume the CPU maximum frequency goes down a bit.

  This was not always the case and seems to have been introduced after a
  kernel update. Sadly, I can't pinpoint which one exactly.

  It can be reproduced on my Lenovo B50-70 even after the latest kernel
  update to 4.2.0-35-generic of Ubuntu 15.10.

  I start by rebooting the system.
  At first, 'sudo cpupower frequency-info' reports a hardware limit of 800 MHz - 2.60 GHz and current policy is between those two.
  Current frequency varies between those based on load.
  Now, I close the lid, reopen and check again.
  Hardware limits are still the same, but policy is now between 800 MHz and 2.08 GHz.
  Repeat and policies maximum keeps dropping. As does the current frequency maximum.
  At some point the policy maximum does not drop any further, but the current frequency maximum does. Way below even the minimum of 800 MHz.

  The expected behaviour is that the current policy matches the hardware
  limits and that the CPU frequency is set between these values.

  Here is the output of 'sudo cpupower frequency-info' after the first
  resume:

  analyzing CPU 0:
    driver: intel_pstate
    CPUs which run at the same hardware frequency: 0
    CPUs which need to have their frequency coordinated by software: 0
    maximum transition latency: 0.97 ms.
    hardware limits: 800 MHz - 2.60 GHz
    available cpufreq governors: performance, powersave
    current policy: frequency should be within 800 MHz and 2.08 GHz.
                    The governor "powersave" may decide which speed to use
                    within this range.
    current CPU frequency is 1.03 GHz (asserted by call to hardware).
    boost state support:
      Supported: yes
      Active: yes
  --- 
  ApportVersion: 2.19.1-0ubuntu5
  Architecture: amd64
  AudioDevicesInUse:
   USER        PID ACCESS COMMAND
   /dev/snd/pcmC1D0p:   erik       1692 F...m pulseaudio
   /dev/snd/controlC1:  erik       1692 F.... pulseaudio
   /dev/snd/controlC0:  erik       1692 F.... pulseaudio
  CurrentDesktop: Unity
  DistroRelease: Ubuntu 15.10
  HibernationDevice: RESUME=UUID=e15f518b-0603-40f2-91f8-a715860f726e
  InstallationDate: Installed on 2015-08-12 (240 days ago)
  InstallationMedia: Ubuntu 15.04 "Vivid Vervet" - Release amd64 (20150422)
  JournalErrors:
   No journal files were found.
   -- No entries --
  MachineType: LENOVO 80EU
  Package: linux (not installed)
  ProcFB: 0 inteldrmfb
  ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.2.0-35-generic.efi.signed root=UUID=d8909dac-cfa5-4a3e-ac20-e5f1e8b01609 ro quiet splash vt.handoff=7
  ProcVersionSignature: Ubuntu 4.2.0-35.40-generic 4.2.8-ckt5
  RelatedPackageVersions:
   linux-restricted-modules-4.2.0-35-generic N/A
   linux-backports-modules-4.2.0-35-generic  N/A
   linux-firmware                            1.149.3
  Tags:  wily
  UdevLog: Error: [Errno 2] No such file or directory: '/var/log/udev'
  Uname: Linux 4.2.0-35-generic x86_64
  UpgradeStatus: Upgraded to wily on 2015-10-25 (165 days ago)
  UserGroups: dialout sudo wireshark
  WifiSyslog:
   
  _MarkForUpload: True
  dmi.bios.date: 08/21/2014
  dmi.bios.vendor: LENOVO
  dmi.bios.version: 9DCN22WW(V2.03)
  dmi.board.asset.tag: No Asset Tag
  dmi.board.name: Lenovo B50-70
  dmi.board.vendor: LENOVO
  dmi.board.version: 31900058WIN
  dmi.chassis.asset.tag: No Asset Tag
  dmi.chassis.type: 10
  dmi.chassis.vendor: LENOVO
  dmi.chassis.version: Lenovo B50-70
  dmi.modalias: dmi:bvnLENOVO:bvr9DCN22WW(V2.03):bd08/21/2014:svnLENOVO:pn80EU:pvrLenovoB50-70:rvnLENOVO:rnLenovoB50-70:rvr31900058WIN:cvnLENOVO:ct10:cvrLenovoB50-70:
  dmi.product.name: 80EU
  dmi.product.version: Lenovo B50-70
  dmi.sys.vendor: LENOVO

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