[PATCH v6 3/4] PCI: dwc: Skip PME_Turn_Off message if there is no endpoint connected

Richard Zhu
2025-09-24T07:24:23Z

A chip freeze is observed on i.MX7D when PCIe RC kicks off the PM_PME
message and no any devices are connected on the port.

To workaroud such kind of issue, skip PME_Turn_Off message if there is
no endpoint connected.

Cc: stable@vger.kernel.org
Fixes: 4774faf854f5 ("PCI: dwc: Implement generic suspend/resume functionality")
Fixes: a528d1a72597 ("PCI: imx6: Use DWC common suspend resume method")
Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
---
drivers/pci/controller/dwc/pcie-designware-host.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index 57a1ba08c427..b303a74b0fd7 100644
--- a/drivers/pci/controller/dwc/pcie-designware-host.c
+++ b/drivers/pci/controller/dwc/pcie-designware-host.c
@@ -1008,12 +1008,15 @@ int dw_pcie_suspend_noirq(struct dw_pcie *pci)
u32 val;
int ret;

- 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;
+ /* Skip PME_Turn_Off message if there is no endpoint connected */
+ if (dw_pcie_get_ltssm(pci) > DW_PCIE_LTSSM_DETECT_WAIT) {
+ 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 (dwc_quirk(pci, QUIRK_NOL2POLL_IN_PM)) {
--
2.37.1