Re: [PATCH v2] PCI: dwc: Proceed with system suspend even if the endpoint doesn't respond with PME_TO_Ack message

[Neil Armstrong <neil.armstrong@linaro.org>]

On 2/17/26 12:31, Manivannan Sadhasivam wrote:
> PCIe spec r7.0, sec 5.3.3.2.1, recommends proceeding with L2/L3 sequence
> even if one or devices do not respond with PME_TO_Ack message after 10ms
> timeout.
> 
> So just print a warning if the timeout happens and proceed with the system
> suspend.
> 
> Reported-by: Neil Armstrong <neil.armstrong@linaro.org>
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
> ---
> 
> Changes in v2:
> 
> * Added 'ret = 0' to avoid failing callers
> 
>   drivers/pci/controller/dwc/pcie-designware-host.c | 10 +++++++---
>   1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
> index 6ae6189e9b8a..ba183fc3e77c 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-host.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
> @@ -1256,9 +1256,13 @@ int dw_pcie_suspend_noirq(struct dw_pcie *pci)
>   				PCIE_PME_TO_L2_TIMEOUT_US/10,
>   				PCIE_PME_TO_L2_TIMEOUT_US, false, pci);
>   	if (ret) {
> -		/* Only log message when LTSSM isn't in DETECT or POLL */
> -		dev_err(pci->dev, "Timeout waiting for L2 entry! LTSSM: 0x%x\n", val);
> -		return ret;
> +		/*
> +		 * Failure is non-fatal since spec r7.0, sec 5.3.3.2.1,
> +		 * recommends proceeding with L2/L3 sequence even if one or more
> +		 * devices do not respond with PME_TO_Ack after 10ms timeout.
> +		 */
> +		dev_warn(pci->dev, "Timeout waiting for L2 entry! LTSSM: 0x%x\n", val);
> +		ret = 0;
>   	}
>   
>   	/*

Allows ath12k to go ind3cold with [1]:

Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8650-HDK

[1] https://lore.kernel.org/all/20260217-d3cold-v2-0-89b322864043@oss.qualcomm.com/