[PATCH v8 2/2] PCI: dwc: Don't return error when wait for link up in dw_pcie_resume_noirq()

[Manivannan Sadhasivam]

On Wed, Jan 14, 2026 at 06:46:23AM +0000, Hongxing Zhu wrote:
> > -----Original Message-----
> > From: Manivannan Sadhasivam <mani at kernel.org>
> > Sent: 2026年1月13日 23:30
> > To: Hongxing Zhu <hongxing.zhu at nxp.com>
> > Cc: Frank Li <frank.li at nxp.com>; jingoohan1 at gmail.com;
> > l.stach at pengutronix.de; lpieralisi at kernel.org; kwilczynski at kernel.org;
> > robh at kernel.org; bhelgaas at google.com; shawnguo at kernel.org;
> > s.hauer at pengutronix.de; kernel at pengutronix.de; festevam at gmail.com;
> > linux-pci at vger.kernel.org; linux-arm-kernel at lists.infradead.org;
> > imx at lists.linux.dev; linux-kernel at vger.kernel.org; stable at vger.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 at vger.kernel.org
> > > Fixes: 4774faf854f5 ("PCI: dwc: Implement generic suspend/resume
> > > functionality")
> > > Signed-off-by: Richard Zhu <hongxing.zhu at nxp.com>
> > > Reviewed-by: Frank Li <Frank.Li at nxp.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.kern/
> > el.org%2Flinux-pci%2F20260107-pci-dwc-suspend-rework-v4-0-9b5f3c72df0a%
> > 40oss.qualcomm.com%2F&data=05%7C02%7Chongxing.zhu%40nxp.com%7Cf8
> > 79871f9d0445aa0a3c08de52b8a2c0%7C686ea1d3bc2b4c6fa92cd99c5c301635
> > %7C0%7C0%7C639039150121991830%7CUnknown%7CTWFpbGZsb3d8eyJFbXB
> > 0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbC
> > IsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=PNdsT530dbRQkgYsrr99gB1cUE
> > BLOkynvciC9tiB0Ic%3D&reserved=0
> >
> > Please test it out.
> Hi Mani:
> You're right.
> Tested on i.MX platforms, no error return anymore. Only "Device not found" is
>  dumped out when no endpoint device is connected. Thanks.
> Tested-by: Richard Zhu <hongxing.zhu at nxp.com>
> 

Please share the tag by replying to that series.

- Mani

-- 
மணிவண்ணன் சதாசிவம்