[PATCH][SRU][Xenial]Fix suspend-to-idle power consumption issue

AceLan Kao acelan.kao at canonical.com
Thu Jun 22 07:41:39 UTC 2017

BugLink: http://bugs.launchpad.net/bugs/1693393

The power consumption under suspend-to-idle(s2idle) are
   8Watt under 4.4 kernel
   4Watt under 4.8 kernel
   2Watt under 4.11 kernel

There are essential patches in 4.8 and 4.11 kernels, they are
In 4.8
   9d26d3a PCI: Put PCIe ports into D3 during suspend
In 4.11
   8d2c453 platform/x86: dell-laptop: Add Latitude 7480 and others to the DMI whitelist

We just have the SRU patch from 4.11(8d2c453) in our proposed kernel,
so we only need the one in 4.8 kernel(9d26d3a).

Using power supply to measure the power consumption, after applied
the 2 patches, the power consumption under s2idle reduce to less than 2Watt.

Sorry to submit again, I forgot to add "cherry picked from" in the patch in
previous submittion.
I know the changes are a little to big for SRU, but it affects 4 Watt power
consumption. And Dell may start to ship their products only with suspend-to-idle
later this year. So, this commit is critical for us, and I can do more
difference testings to make you feel confortable.

Mika Westerberg (1):
  PCI: Put PCIe ports into D3 during suspend

 Documentation/kernel-parameters.txt |   4 +
 drivers/pci/bus.c                   |   1 +
 drivers/pci/pci-driver.c            |   5 +-
 drivers/pci/pci-sysfs.c             |   5 ++
 drivers/pci/pci.c                   | 175 ++++++++++++++++++++++++++++++++++++
 drivers/pci/pci.h                   |  11 +++
 drivers/pci/remove.c                |   2 +
 drivers/usb/host/xhci-pci.c         |   2 +-
 include/linux/pci.h                 |   3 +
 9 files changed, 203 insertions(+), 5 deletions(-)


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