Re: [PATCH v6 0/3] PCI: qcom: Implement shutdown() to avoid SMMU/NoC errors on reboot

[Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>]

On 9/9/26 2:24 PM, Krishna Chaitanya Chundru wrote:
> During system shutdown/reboot, power/clocks to the PCIe controller get
> removed regardless of link state. If the link is still up when that
> happens, it can trigger SMMU or NoC errors.
> 
> This series adds a shutdown() callback to the Qualcomm PCIe host driver
> that forces the link into L2/D3cold before shutdown proceeds, reusing
> the existing suspend_noirq() path.
> 
> Patch 1 fixes pci_host_common_d3cold_possible()'s underlying bus walk,
> which aborts as soon as it finds a device outside D3hot and can
> therefore miss a later PME-capable device -- something that becomes
> common once patch 3 starts forcing D3cold entry during shutdown while
> endpoints may still be in D0.
> 
> Patch 2 adds a force parameter to  dw_pcie_suspend_noirq() so that callers can
> set to make dw_pcie_suspend_noirq() force L2 entry during shutdown/
> reboot, skipping the D3cold capability check that can otherwise leave
> the link up if any endpoint hasn't suspended yet.
> 
> Patch 3 adds qcom_pcie_shutdown() and wires it up as .shutdown.
> 
> Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
> ---
> Changes in v6:
> - remove return 0 in d3cold_possible() (konrad)

I re-read it once again and I'm not sure my comment was right..

Konrad