4.19-stable review patch. If anyone has any objections, please let me know.
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From: Lucas Stach l.stach@pengutronix.de
commit 3afc8299f39a27b60e1519a28e18878ce878e7dd upstream.
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.
Fixes: 7c5925afbc58 ("PCI: dwc: Move MSI IRQs allocation to IRQ domains hierarchical API") Tested-by: Tim Harvey tharvey@gateworks.com Signed-off-by: Lucas Stach l.stach@pengutronix.de Signed-off-by: Lorenzo Pieralisi lorenzo.pieralisi@arm.com Acked-by: Gustavo Pimentel gustavo.pimentel@synopsys.com Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/pci/controller/dwc/pcie-designware-host.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/pci/controller/dwc/pcie-designware-host.c +++ b/drivers/pci/controller/dwc/pcie-designware-host.c @@ -439,7 +439,7 @@ int dw_pcie_host_init(struct pcie_port * 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