[PATCH v2] PCI: dwc: Proceed with system suspend even if the endpoint doesn't respond with PME_TO_Ack message

[Manivannan Sadhasivam]

PCIe spec r7.0, sec 5.3.3.2.1, recommends proceeding with L2/L3 sequence
even if one or devices do not respond with PME_TO_Ack message after 10ms
timeout.

So just print a warning if the timeout happens and proceed with the system
suspend.

Reported-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxxxxxxxx>
---

Changes in v2:

* Added 'ret = 0' to avoid failing callers

 drivers/pci/controller/dwc/pcie-designware-host.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index 6ae6189e9b8a..ba183fc3e77c 100644
--- a/drivers/pci/controller/dwc/pcie-designware-host.c
+++ b/drivers/pci/controller/dwc/pcie-designware-host.c
@@ -1256,9 +1256,13 @@ int dw_pcie_suspend_noirq(struct dw_pcie *pci)
 				PCIE_PME_TO_L2_TIMEOUT_US/10,
 				PCIE_PME_TO_L2_TIMEOUT_US, false, pci);
 	if (ret) {
-		/* Only log message when LTSSM isn't in DETECT or POLL */
-		dev_err(pci->dev, "Timeout waiting for L2 entry! LTSSM: 0x%x\n", val);
-		return ret;
+		/*
+		 * Failure is non-fatal since spec r7.0, sec 5.3.3.2.1,
+		 * recommends proceeding with L2/L3 sequence even if one or more
+		 * devices do not respond with PME_TO_Ack after 10ms timeout.
+		 */
+		dev_warn(pci->dev, "Timeout waiting for L2 entry! LTSSM: 0x%x\n", val);
+		ret = 0;
 	}
 
 	/*
-- 
2.51.0