| Message ID | 20241209073924.2155933-2-hongxing.zhu@nxp.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Bug fixes when dwc generic suspend/resume callbacks are used | expand |
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@nxp.com> > Reviewed-by: Frank Li <Frank.Li@nxp.com> > --- > .../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. > > - 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)
Best Regards Richard Zhu > -----Original Message----- > From: Damien Le Moal <dlemoal@kernel.org> > Sent: 2024年12月9日 16:50 > To: Hongxing Zhu <hongxing.zhu@nxp.com>; jingoohan1@gmail.com; > bhelgaas@google.com; lpieralisi@kernel.org; kw@linux.com; > manivannan.sadhasivam@linaro.org; robh@kernel.org; Frank Li > <frank.li@nxp.com>; quic_krichai@quicinc.com > Cc: imx@lists.linux.dev; kernel@pengutronix.de; linux-pci@vger.kernel.org; > linux-kernel@vger.kernel.org > 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@nxp.com> > > Reviewed-by: Frank Li <Frank.Li@nxp.com> > > --- > > .../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
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; - 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)
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@nxp.com> Reviewed-by: Frank Li <Frank.Li@nxp.com> --- .../pci/controller/dwc/pcie-designware-host.c | 30 +++++++++---------- 1 file changed, 15 insertions(+), 15 deletions(-)