[dpdk-dev] [PATCH 2/2] igb_uio: handle no IRQ fallback

[Stephen Hemminger]

Fix a couple of issues with my earlier igb_uio stuff:
1. With MSI (like MSI-X) actual IRQ number is not known until
   after the pci_enable_msi() is done.
2. If INTX fails, fall back to running without IRQ.
   This allows usermode PCI to recover and run without out IRQ
   for cases where PCI INTX support is broken (aka VMWare).
Signed-off-by: Stephen Hemminger <stephen at networkplumber.org>


--- a/lib/librte_eal/linuxapp/igb_uio/igb_uio.c 2014-07-25 10:30:07.740159856 
-0700
+++ b/lib/librte_eal/linuxapp/igb_uio/igb_uio.c 2014-07-25 10:30:07.736159842 
-0700
@@ -506,7 +506,6 @@ igbuio_pci_probe(struct pci_dev *dev, co
        udev->info.version = "0.1";
        udev->info.handler = igbuio_pci_irqhandler;
        udev->info.irqcontrol = igbuio_pci_irqcontrol;
-       udev->info.irq = dev->irq;
 #ifdef CONFIG_XEN_DOM0
        /* check if the driver run on Xen Dom0 */
        if (xen_initial_domain())
@@ -516,9 +515,6 @@ igbuio_pci_probe(struct pci_dev *dev, co
        udev->pdev = dev;

        switch (igbuio_intr_mode_preferred) {
-       case RTE_INTR_MODE_NONE:
-               udev->info.irq = 0;
-               break;
        case RTE_INTR_MODE_MSIX:
                /* Only 1 msi-x vector needed */
                msix_entry.entry = 0;
@@ -532,6 +528,7 @@ igbuio_pci_probe(struct pci_dev *dev, co
        case RTE_INTR_MODE_MSI:
                if (pci_enable_msi(dev) == 0) {
                        dev_dbg(&dev->dev, "using MSI");
+                       udev->info.irq = dev->irq;
                        udev->mode = RTE_INTR_MODE_MSI;
                        break;
                }
@@ -540,13 +537,17 @@ igbuio_pci_probe(struct pci_dev *dev, co
                if (pci_intx_mask_supported(dev)) {
                        dev_dbg(&dev->dev, "using INTX");
                        udev->info.irq_flags = IRQF_SHARED;
+                       udev->info.irq = dev->irq;
                        udev->mode = RTE_INTR_MODE_LEGACY;
-               } else {
-                       dev_err(&dev->dev, "PCI INTX mask not supported\n");
-                       err = -EIO;
-                       goto fail_release_iomem;
+                       break;
                }
+               dev_notice(&dev->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 = 0;
                break;
+
        default:
                dev_err(&dev->dev, "invalid IRQ mode %u",
                        igbuio_intr_mode_preferred);