Re: [PATCH v2] PCI: qcom: Power the controller down when hibernating

[sashiko-bot@kernel.org]

> qcom_pcie_suspend_noirq() leaves the controller powered when a device
> below it cannot go to D3cold, and qcom_pcie_resume_noirq() then carries
> on with the controller as it was.
> 
> That is fine for suspend. The same two functions also run as
> freeze_noirq and restore_noirq for hibernation. Devices are normally
> still in D0 at freeze, so a controller with a device behind it is left
> powered and the image records it as running. That image is resumed
> after a power cycle, by a kernel that may never have brought the
> controller up.
> 
> On a Lenovo Yoga Slim 7x (X1E80100) this resets the machine on every
> resume from hibernation. The Wi-Fi card is behind pcie4, whose link
> only comes up once the power sequencing drivers have been loaded from
> the root file system. The kernel that loads the image resumes before
> [ ... ]
> dw_pcie_resume_noirq(), like after any other loss of power. Suspend and
> the poweroff phase of hibernation keep the D3cold check.
> 
> Suggested-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
> Signed-off-by: Birk Skyum <birk.skyum@pm.me>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/179181074907.22199.10556821368232442334@pm.me?part=1