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

[Konrad Dybcio]

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?

Konrad