PCI: dwc: Remove MSI/MSIX capability if iMSI-RX is used as … (#408)

FROMLIST: PCI: dwc: Remove MSI/MSIX capability if iMSI-RX is used as …

Author: sgaud-quic

drivers/pci/controller/dwc/pcie-designware-host.c

@@ -1106,6 +1106,16 @@ int dw_pcie_setup_rc(struct dw_pcie_rp *pp)
 
 	dw_pcie_dbi_ro_wr_dis(pci);
 
+	/*
+	 * If iMSI-RX module is used as the MSI controller, remove MSI and
+	 * MSI-X capabilities from PCIe Root Ports to ensure fallback to INTx
+	 * interrupt handling.
+	 */
+	if (pp->has_msi_ctrl) {
+		dw_pcie_remove_capability(pci, PCI_CAP_ID_MSI);
+		dw_pcie_remove_capability(pci, PCI_CAP_ID_MSIX);
+	}
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(dw_pcie_setup_rc);