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

[Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>]

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@oss.qualcomm.com>
>> ---
> [...]
>
>>   		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