Merge branch 'pci/enumeration'

- Clear LBMS bit after a manual link retrain so we don't try to retrain a
  link when there's no downstream device anymore (Maciej W. Rozycki)

- Revert to the original link speed after retraining fails instead of
  leaving it restricted to 2.5GT/s, so a future device has a chance to use
  higher speeds (Maciej W. Rozycki)

- Correct interpretation of pcie_retrain_link() return status and update it
  to return 0/errno instead of true/false (Maciej W.  Rozycki)

* pci/enumeration:
  PCI: Use an error code with PCIe failed link retraining
  PCI: Correct error reporting with PCIe failed link retraining
  PCI: Revert to the original speed after PCIe failed link retraining
  PCI: Clear the LBMS bit after a link retrain

1 files changed, 10 insertions, 2 deletions

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 55d6124acb2d..7148a3d4ec8d 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1339,7 +1339,7 @@ static int pci_dev_wait(struct pci_dev *dev, char *reset_type, int timeout)
 		if (delay > PCI_RESET_WAIT) {
 			if (retrain) {
 				retrain = false;
-				if (pcie_failed_link_retrain(bridge)) {
+				if (pcie_failed_link_retrain(bridge) == 0) {
 					delay = 1;
 					continue;
 				}
@@ -4732,7 +4732,15 @@ int pcie_retrain_link(struct pci_dev *pdev, bool use_lt)
 		pcie_capability_clear_word(pdev, PCI_EXP_LNKCTL, PCI_EXP_LNKCTL_RL);
 	}
 
-	return pcie_wait_for_link_status(pdev, use_lt, !use_lt);
+	rc = pcie_wait_for_link_status(pdev, use_lt, !use_lt);
+
+	/*
+	 * Clear LBMS after a manual retrain so that the bit can be used
+	 * to track link speed or width changes made by hardware itself
+	 * in attempt to correct unreliable link operation.
+	 */
+	pcie_capability_write_word(pdev, PCI_EXP_LNKSTA, PCI_EXP_LNKSTA_LBMS);
+	return rc;
 }
 
 /**