+ /* fall back to MSI */
+ case RTE_INTR_MODE_MSI:
+#ifndef HAVE_ALLOC_IRQ_VECTORS
+ if (pci_enable_msi(udev->pdev) == 0) {
+ dev_dbg(&udev->pdev->dev, "using MSI");
+ udev->info.irq_flags = IRQF_NO_THREAD;
+ udev->info.irq = udev->pdev->irq;
+ udev->mode = RTE_INTR_MODE_MSI;
+ break;
+ }
+#else
+ if (pci_alloc_irq_vectors(udev->pdev, 1, 1, PCI_IRQ_MSI) == 1) {
+ dev_dbg(&udev->pdev->dev, "using MSI");
+ udev->info.irq_flags = IRQF_NO_THREAD;
+ udev->info.irq = pci_irq_vector(udev->pdev, 0);
+ udev->mode = RTE_INTR_MODE_MSI;
+ break;
+ }
+#endif
+ /* fall back to INTX */
+ case RTE_INTR_MODE_LEGACY:
+ if (pci_intx_mask_supported(udev->pdev)) {
+ dev_dbg(&udev->pdev->dev, "using INTX");
+ udev->info.irq_flags = IRQF_SHARED | IRQF_NO_THREAD;
+ udev->info.irq = udev->pdev->irq;
+ udev->mode = RTE_INTR_MODE_LEGACY;
+ break;
+ }
+ dev_notice(&udev->pdev->dev, "PCI INTX mask not supported\n");
+ /* fall back to no IRQ */
+ case RTE_INTR_MODE_NONE:
+ udev->mode = RTE_INTR_MODE_NONE;
+ udev->info.irq = UIO_IRQ_NONE;
+ break;
+
+ default:
+ dev_err(&udev->pdev->dev, "invalid IRQ mode %u",
+ igbuio_intr_mode_preferred);
+ udev->info.irq = UIO_IRQ_NONE;
+ err = -EINVAL;
+ }
+
+ if (udev->info.irq != UIO_IRQ_NONE)
+ err = request_irq(udev->info.irq, igbuio_pci_irqhandler,
+ udev->info.irq_flags, udev->info.name,
+ udev);
+ dev_info(&udev->pdev->dev, "uio device registered with irq %lx\n",
+ udev->info.irq);
+
+ return err;