Re: [PATCH v8 2/4] PCI: dwc: Force L2 link entry on shutdown/reboot without D3cold check

[sashiko-bot@kernel.org]

> dw_pcie_suspend_noirq() normally calls pci_host_common_d3cold_possible()
> to check whether every downstream endpoint can be put into D3cold before
> bothering to move the link to L2. If no endpoint supports it, the
> function returns early and leaves the link up.
> 
> Querying D3cold support during shutdown is actively harmful, not just
> slow: pci_host_common_d3cold_possible() requires every active endpoint
> to already be in PCI_D3hot, and returns false otherwise. If any endpoint
> is still in D0 -- which is common, since endpoint drivers aren't
> guaranteed to have suspended by the time the host's shutdown path runs
> the check fails and dw_pcie_suspend_noirq() returns early without ever
> moving the link to L2, leaving it up right up to the point where the
> system cuts power/clocks to the controller.
> 
> Add a force parameter to dw_pcie_suspend_noirq() that callers set
> explicitly to force this behavior, still call
> pci_host_common_d3cold_possible() unconditionally, since it's also how
> pme_capable gets set, but ignore its return value and force L2 entry
> regardless when force is set.
> 
> Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261107-shutdown-v8-0-bf607c6429b0@oss.qualcomm.com?part=2