[PATCH 3.18 04/39] PCI: designware: Reject MSI-X IRQs

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

3.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Lucas Stach <l.stach@pengutronix.de>

commit 19c5392eb1c1e81188e898400c0e8258827eb160 upstream.

The DesignWare PCIe MSI hardware does not support MSI-X IRQs.  Setting
those up failed as a side effect of a bug which was fixed by 91f8ae823f2b
("PCI: designware: Setup and clear exactly one MSI at a time").

Now that this bug is fixed, MSI-X IRQs need to be rejected explicitly;
otherwise devices trying to use them may end up with incorrectly working
interrupts.

Fixes: 91f8ae823f2b ("PCI: designware: Setup and clear exactly one MSI at a time")
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/pci/host/pcie-designware.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/pci/host/pcie-designware.c
+++ b/drivers/pci/host/pcie-designware.c
@@ -283,6 +283,9 @@ static int dw_msi_setup_irq(struct msi_c
 	struct msi_msg msg;
 	struct pcie_port *pp = sys_to_pcie(pdev->bus->sysdata);
 
+	if (desc->msi_attrib.is_msix)
+		return -EINVAL;
+
 	irq = assign_irq(1, desc, &pos);
 	if (irq < 0)
 		return irq;