PowerManagementASPM

Revision 10 as of 2011-11-12 19:37:24

Clear message

ASPM PCIe Bug

As noted by Phoronix ASPM PCIe power saving has been problematic and a recent patch by Matthew Garrett has re-worked this to clear the ASPM state on all devices on a successful handoff of PCIe control to the OS.

We therefore are providing patched kernels carrying Matthew's fix for testing purposes only to see how well this works across a broad range of machines. Kernels can be found in:

For power measurement, we currently recommend using the older version of powertop 1.13 as this clearly displays the ACPI estimated power consumption. A .deb for this can be found here. We recommend running powertop as follows:

  • Boot the machine, start powertop 1.13
  • Wait until you get an ACPI estimated power consumption value.
  • Gather 15 measurements (it is updated regularly).
  • Discard the 5 results.
  • Take average of the last 10 results.

Testing procedure:

  • Ensure laptop is fully charged
  • Unplug AC power
  • Run powertop on an idle system and note power consumption
  • Plug in AC power
  • Install the new kernel containing the ASPM fix
  • Ensure laptop is fully charged
  • Unplug AC power
  • Run powertop on an idle system and note power consumption
  • Gather the BIOS version using: sudo dmidecode -t 0 | grep "Version:"
  • Add results to the table below:

Machine

BIOS

32/64 bit kernel

Original Kernel

Original Kernel Power

ASPM fix Kernel

ASPM fix Power

Lenovo 3000N200

68ET27WW

64

3.1.0-2-generic

24.3W

3.1.0-2-generic

25.4W

HP Mini 210

F0.2

64

3.0.0-12-generic

14.3W

3.0.0-13-generic

8.7W

HP ProBook 5420s

68AZZ Ver. F.0F

64

3.0.0-12-generic

25.06W

3.0.0-13-generic

25.66W

Lenovo Thinkpad X301

6EET54WW (3.14 )

64

3.1.0-2-generic

11.4W

3.1.0-2-generic

11.4W