FAILED: patch "[PATCH] PCI: dwc: skip MSI init if MSIs have been explicitly disabled" failed to apply to 4.14-stable tree

The patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 3afc8299f39a27b60e1519a28e18878ce878e7dd Mon Sep 17 00:00:00 2001
From: Lucas Stach <[email protected]>
Date: Wed, 27 Feb 2019 17:52:19 +0100
Subject: [PATCH] PCI: dwc: skip MSI init if MSIs have been explicitly disabled

Since 7c5925afbc58 (PCI: dwc: Move MSI IRQs allocation to IRQ domains hierarchical API) the MSI init claims one of the controller IRQs as a chained IRQ line for the MSI controller. On some designs, like the i.MX6, this line is shared with a PCIe legacy IRQ. When the line is claimed for the MSI domain, any device trying to use this legacy IRQs will fail to request this IRQ line.

As MSI and legacy IRQs are already mutually exclusive on the DWC core, as the core won't forward any legacy IRQs once any MSI has been enabled, users wishing to use legacy IRQs already need to explictly disable MSI support (usually via the pci=nomsi kernel commandline option). To avoid any issues with MSI conflicting with legacy IRQs, just skip all of the DWC MSI initalization, including the IRQ line claim, when MSI is disabled.

index 0c18ab63811f..25087d3c9a82 100644
@@ -439,7 +439,7 @@ int dw_pcie_host_init(struct pcie_port *pp)
 	if (ret)
 		pci->num_viewport = 2;
 
-	if (IS_ENABLED(CONFIG_PCI_MSI)) {
+	if (IS_ENABLED(CONFIG_PCI_MSI) && pci_msi_enabled()) {
 		/*
 		 * If a specific SoC driver needs to change the
 		 * default number of vectors, it needs to implement