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

[Konrad Dybcio]

On 4/7/26 1:37 PM, Krishna Chaitanya Chundru wrote:
> 
> 
> 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

OK, thanks for confirming

Konrad