On Tue, May 02, 2017 at 07:20:59AM -0700, Jim Harris wrote:
> Some userspace drivers and frameworks only poll and do not
> require interrupts to be available and enabled on the
> PCI device. So remove the requirement that an IRQ is
> assigned. If an IRQ is not assigned and a userspace
> driver tries to read()/write(), the generic uio
> framework will just return -EIO.
>
> This allows binding uio_pci_generic to devices which
> cannot get an IRQ assigned, such as an NVMe controller
> behind Intel Volume Management Device (VMD), since VMD
> does not support INTx interrupts.
>
> Signed-off-by: Jim Harris <james.r.harris@xxxxxxxxx>
I'm still not sure why such a stub is useful, but it seems
harmless.
Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
> ---
> drivers/uio/uio_pci_generic.c | 20 +++++++++-----------
> 1 file changed, 9 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/uio/uio_pci_generic.c b/drivers/uio/uio_pci_generic.c
> index d0b508b68f3c..a56fdf972dbe 100644
> --- a/drivers/uio/uio_pci_generic.c
> +++ b/drivers/uio/uio_pci_generic.c
> @@ -66,14 +66,7 @@ static int probe(struct pci_dev *pdev,
> return err;
> }
>
> - if (!pdev->irq) {
> - dev_warn(&pdev->dev, "No IRQ assigned to device: "
> - "no support for interrupts?\n");
> - pci_disable_device(pdev);
> - return -ENODEV;
> - }
> -
> - if (!pci_intx_mask_supported(pdev)) {
> + if (pdev->irq && !pci_intx_mask_supported(pdev)) {
> err = -ENODEV;
> goto err_verify;
> }
> @@ -86,10 +79,15 @@ static int probe(struct pci_dev *pdev,
>
> gdev->info.name = "uio_pci_generic";
> gdev->info.version = DRIVER_VERSION;
> - gdev->info.irq = pdev->irq;
> - gdev->info.irq_flags = IRQF_SHARED;
> - gdev->info.handler = irqhandler;
> gdev->pdev = pdev;
> + if (pdev->irq) {
> + gdev->info.irq = pdev->irq;
> + gdev->info.irq_flags = IRQF_SHARED;
> + gdev->info.handler = irqhandler;
> + } else {
> + dev_warn(&pdev->dev, "No IRQ assigned to device: "
> + "no support for interrupts?\n");
> + }
>
> err = uio_register_device(&pdev->dev, &gdev->info);
> if (err)
> --
> 2.12.2
