linux-kernel - Re: [PATCH v8 2/2] PCI: dwc: Don't return error when wait for link up in dw_pcie_resume

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Message-ID: <7akwvdfve5jcj2tm7jiwowkvcctsmqeslia4pulvtdgcgicp4p@h5ztwyp4h7ft>
Date: Tue, 13 Jan 2026 20:59:58 +0530
From: Manivannan Sadhasivam <mani@...nel.org>
To: Richard Zhu <hongxing.zhu@....com>
Cc: frank.li@....com, jingoohan1@...il.com, l.stach@...gutronix.de, 
	lpieralisi@...nel.org, kwilczynski@...nel.org, robh@...nel.org, bhelgaas@...gle.com, 
	shawnguo@...nel.org, s.hauer@...gutronix.de, kernel@...gutronix.de, 
	festevam@...il.com, linux-pci@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
	imx@...ts.linux.dev, linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH v8 2/2] PCI: dwc: Don't return error when wait for link
 up in dw_pcie_resume_noirq()

On Wed, Jan 07, 2026 at 10:45:53AM +0800, Richard Zhu wrote:
> When waiting for the PCIe link to come up, both link up and link down
> are valid results depending on the device state.
> 
> Since the link may come up later and to get rid of the following
> mis-reported PM errors. Do not return an -ETIMEDOUT error, as the
> outcome has already been reported in dw_pcie_wait_for_link().
> 
> PM error logs introduced by the -ETIMEDOUT error return.
> imx6q-pcie 33800000.pcie: Phy link never came up
> imx6q-pcie 33800000.pcie: PM: dpm_run_callback(): genpd_resume_noirq returns -110
> imx6q-pcie 33800000.pcie: PM: failed to resume noirq: error -110
> 
> Cc: stable@...r.kernel.org
> Fixes: 4774faf854f5 ("PCI: dwc: Implement generic suspend/resume functionality")
> Signed-off-by: Richard Zhu <hongxing.zhu@....com>
> Reviewed-by: Frank Li <Frank.Li@....com>
> ---
>  drivers/pci/controller/dwc/pcie-designware-host.c | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
> index 06cbfd9e1f1e..025e11ebd571 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-host.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
> @@ -1245,10 +1245,9 @@ int dw_pcie_resume_noirq(struct dw_pcie *pci)
>  	if (ret)
>  		return ret;
>  
> -	ret = dw_pcie_wait_for_link(pci);
> -	if (ret)
> -		return ret;
> +	/* Ignore errors, the link may come up later */
> +	dw_pcie_wait_for_link(pci);

It is not safe to ignore failures during resume. Because, if a device gets
removed during suspend, the link up error will be unnoticed. I've proposed a
different logic in this series, which should address your issue:
https://lore.kernel.org/linux-pci/20260107-pci-dwc-suspend-rework-v4-0-9b5f3c72df0a@oss.qualcomm.com/

Please test it out.

- Mani

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