Re: [PATCH v3 5/5] PCI: qcom: Add D3cold support

[Krishna Chaitanya Chundru]

On 3/17/2026 2:45 PM, Konrad Dybcio wrote:
> On 3/11/26 11:26 AM, Krishna Chaitanya Chundru wrote:
> > Add support for transitioning PCIe endpoints & bridges into D3cold by
> > integrating with the DWC core suspend/resume helpers.
> >
> > Implement PME_TurnOff message generation via ELBI_SYS_CTRL and hook it
> > into the DWC host operations so the controller follows the standard
> > PME_TurnOff-based power-down sequence before entering D3cold.
> >
> > When the device is suspended into D3cold, fully tear down interconnect
> > bandwidth, OPP votes. If D3cold is not entered, retain existing behavior
> > by keeping the required interconnect and OPP votes.
> >
> > Drop the qcom_pcie::suspended flag and rely on the existing
> > dw_pcie::suspended state, which now drives both the power-management
> > flow and the interconnect/OPP handling.
> >
> > Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@xxxxxxxxxxxxxxxx>
> > ---
> [...]
>
> >   		ret = icc_disable(pcie->icc_cpu);
> >   		if (ret)
> >   			dev_err(dev, "Failed to disable CPU-PCIe interconnect path: %d\n", ret);
> >   
> >   		if (pcie->use_pm_opp)
> >   			dev_pm_opp_set_opp(pcie->pci->dev, NULL);
> Does calling .suspend not drop the vote by itself?
No, unlike genpd framework for power domains, opp votes will not removed 
as part of suspend.

- Krishna Chaitanya.
> [...]
>
> > @@ -2132,25 +2138,46 @@ static int qcom_pcie_resume_noirq(struct device *dev)
> Similarly, I'd expect that .resume restores it (and you didn't do it manually)
>
> Konrad