[Resend] [SRU] [B/C/D/Unstable] [PATCH 0/2] Power consumption during s2idle is higher than long idle (Intel SSDPEKKF)

[Kai-Heng Feng]

BugLink: https://bugs.launchpad.net/bugs/1804588

[Impact]
On new systems that facilitate s2idle, we observed the power consumption
raises higher than long idle does during s2idle with Intel NVMe
SSDPEKKF.

Short idle: 6
Long idle: 2
S2I: 4.8

[Fix]
Windows doesn't put nvme to D3 in modern standby, and uses its own APST
feature to do the power management. To leverage its APST feature during
s2idle, we can't disable nvme device while suspending, too.
So, here is what we did on the driver, 1. prevent nvme from entering D3,
2. prevent nvme from being disabled when suspending.

[Test]
Verified on the new Intel NVMe, it fixes the power consumption issue
with no regression. And the power consumption decreases to 2.8W during
s2idle.

[Regression Potential]
Low, the patches only applied to specific nvme module, and from our
test, the system is still stable.

Kai-Heng Feng (2):
  SAUCE: pci: prevent Intel NVMe SSDPEKKF from entering D3
  SAUCE: nvme: add quirk to not call disable function when suspending

 drivers/nvme/host/pci.c | 2 ++
 drivers/pci/quirks.c    | 1 +
 2 files changed, 3 insertions(+)

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2.17.1