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

[Krishna Chaitanya Chundru]

On 4/7/2026 5:06 PM, Konrad Dybcio wrote:
> On 4/6/26 11:08 AM, Krishna Chaitanya Chundru wrote:
>>
>> 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.
> Hm, I would imagine the power vote goes down.. is that the ICC vote
> that's still hanging if we don't do this?
yes, ICC votes are still present

- Krishna Chaitanya.
> Konrad