Re: [PATCH v4 9/9] PCI: dwc: support missing PCIe device on resume

[Bjorn Helgaas <helgaas@kernel.org>]

On Wed, Oct 29, 2025 at 06:56:48PM +0100, Sebastian Reichel wrote:
> When dw_pcie_resume_noirq() is called for a PCIe root complex for a PCIe
> slot with no device plugged on Rockchip RK3576, dw_pcie_wait_for_link()
> will return -ETIMEDOUT. During probe time this does not happen, since
> the platform sets 'use_linkup_irq'.
> 
> This adds the same logic from dw_pcie_host_init() to the PM resume
> function to avoid the problem.

s/PCI: dwc: support/PCI: dwc: Support/  (in subject; capitalize first word)
s/This adds/Add/

Can you mention 8d3bf19f1b58 ("PCI: dwc: Don't wait for link up if
driver can detect Link Up event") here?  I think that's what added the
similar probe-time code.

I see you did copy the comment from 8d3bf19f1b58, thanks for that!

Maybe also word your subject and commit log along the same lines so
the two commits are easier to connect to each other.

> Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
> ---
>  drivers/pci/controller/dwc/pcie-designware-host.c | 13 ++++++++++---
>  1 file changed, 10 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
> index e92513c5bda5..f25f1c136900 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-host.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
> @@ -1215,9 +1215,16 @@ int dw_pcie_resume_noirq(struct dw_pcie *pci)
>  	if (ret)
>  		return ret;
>  
> -	ret = dw_pcie_wait_for_link(pci);
> -	if (ret)
> -		return ret;
> +	/*
> +	 * Note: Skip the link up delay only when a Link Up IRQ is present.
> +	 * If there is no Link Up IRQ, we should not bypass the delay
> +	 * because that would require users to manually rescan for devices.
> +	 */
> +	if (!pci->pp.use_linkup_irq) {
> +		ret = dw_pcie_wait_for_link(pci);
> +		if (ret)
> +			return ret;
> +	}
>  
>  	return ret;
>  }
> 
> -- 
> 2.51.0
>