Best Regards
Richard Zhu
> -----Original Message-----
> From: Damien Le Moal <dlemoal@xxxxxxxxxx>
> Sent: 2024年12月9日 16:50
> To: Hongxing Zhu <hongxing.zhu@xxxxxxx>; jingoohan1@xxxxxxxxx;
> bhelgaas@xxxxxxxxxx; lpieralisi@xxxxxxxxxx; kw@xxxxxxxxx;
> manivannan.sadhasivam@xxxxxxxxxx; robh@xxxxxxxxxx; Frank Li
> <frank.li@xxxxxxx>; quic_krichai@xxxxxxxxxxx
> Cc: imx@xxxxxxxxxxxxxxx; kernel@xxxxxxxxxxxxxx; linux-pci@xxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v3 1/3] PCI: dwc: Fix resume failure if no EP is connected on
> some platforms
>
> On 12/9/24 16:39, Richard Zhu wrote:
> > The dw_pcie_suspend_noirq() function currently returns success
> > directly if no endpoint (EP) device is connected. However, on some
> > platforms, power loss occurs during suspend, causing dw_resume() to do
> > nothing in this case. This results in a system halt because the DWC
> > controller is not initialized after power-on during resume.
> >
> > Call deinit() in suspend and init() at resume regardless of whether
> > there are EP device connections or not. It is not harmful to perform
> > deinit() and init() again for the no power-off case, and it keeps the
> > code simple and consistent in logic.
> >
> > Fixes: 4774faf854f5 ("PCI: dwc: Implement generic suspend/resume
> > functionality")
> > Signed-off-by: Richard Zhu <hongxing.zhu@xxxxxxx>
> > Reviewed-by: Frank Li <Frank.Li@xxxxxxx>
> > ---
> > .../pci/controller/dwc/pcie-designware-host.c | 30
> > +++++++++----------
> > 1 file changed, 15 insertions(+), 15 deletions(-)
> >
> > diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c
> > b/drivers/pci/controller/dwc/pcie-designware-host.c
> > index f882b11fd7b94..11563402c571b 100644
> > --- a/drivers/pci/controller/dwc/pcie-designware-host.c
> > +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
> > @@ -982,23 +982,23 @@ int dw_pcie_suspend_noirq(struct dw_pcie *pci)
> > if (dw_pcie_readw_dbi(pci, offset + PCI_EXP_LNKCTL) &
> PCI_EXP_LNKCTL_ASPM_L1)
> > return 0;
> >
> > - if (dw_pcie_get_ltssm(pci) <= DW_PCIE_LTSSM_DETECT_ACT)
> > - return 0;
> > -
> > - if (pci->pp.ops->pme_turn_off)
> > - pci->pp.ops->pme_turn_off(&pci->pp);
> > - else
> > - ret = dw_pcie_pme_turn_off(pci);
> > + /* Only send out PME_TURN_OFF when PCIE link is up */
> > + if (dw_pcie_get_ltssm(pci) > DW_PCIE_LTSSM_DETECT_ACT) {
> > + if (pci->pp.ops->pme_turn_off)
> > + pci->pp.ops->pme_turn_off(&pci->pp);
> > + else
> > + ret = dw_pcie_pme_turn_off(pci);
> >
> > - if (ret)
> > - return ret;
> > + if (ret)
> > + return ret;
>
> Same comment as for patch 3. This "if (ret) return ret;" can go inside the else.
> It is harmless, but there is also no point in having it here.
>
Hi Damien:
Okay, thanks.
BTW, I'm considering that the use-case of #1 patch had been covered by #3
commit already.
Since, the PME_TURN_OFF would be kicked off without LTSSM stat check in #3.
To be simple, how about drop the #1 patch, re-format the codes, and add one
Fixes tag into #3?
Best Regards
Richard Zhu
> >
> > - ret = read_poll_timeout(dw_pcie_get_ltssm, val, val ==
> DW_PCIE_LTSSM_L2_IDLE,
> > - PCIE_PME_TO_L2_TIMEOUT_US/10,
> > - PCIE_PME_TO_L2_TIMEOUT_US, false, pci);
> > - if (ret) {
> > - dev_err(pci->dev, "Timeout waiting for L2 entry! LTSSM: 0x%x\n", val);
> > - return ret;
> > + ret = read_poll_timeout(dw_pcie_get_ltssm, val, val ==
> DW_PCIE_LTSSM_L2_IDLE,
> > + PCIE_PME_TO_L2_TIMEOUT_US/10,
> > + PCIE_PME_TO_L2_TIMEOUT_US, false, pci);
> > + if (ret) {
> > + dev_err(pci->dev, "Timeout waiting for L2 entry! LTSSM: 0x%x\n",
> val);
> > + return ret;
> > + }
> > }
> >
> > if (pci->pp.ops->deinit)
>
>
> --
> Damien Le Moal
> Western Digital Research
