From: "Michael S. Tsirkin" <mst@redhat.com>
To: Jim Harris <james.r.harris@intel.com>
Cc: kvm@vger.kernel.org, gregkh@linuxfoundation.org,
linux@vger.kernel.org, keith.busch@intel.com,
jonathan.derrick@intel.com
Subject: Re: [PATCH] uio/uio_pci_generic: don't fail probe if pdev->irq == NULL
Date: Mon, 1 May 2017 04:17:28 +0300 [thread overview]
Message-ID: <20170501041652-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20170430192955.9098-1-james.r.harris@intel.com>
On Sun, Apr 30, 2017 at 12:29:55PM -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@intel.com>
Without interrupts, why do you want uio? All it does is
forward interrupts to userspace.
> ---
> 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..81c59b4f8552 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 (pci->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
next prev parent reply other threads:[~2017-05-01 1:17 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-30 19:29 [PATCH] uio/uio_pci_generic: don't fail probe if pdev->irq == NULL Jim Harris
2017-05-01 1:17 ` Michael S. Tsirkin [this message]
2017-05-01 21:21 ` Harris, James R
2017-05-02 9:20 ` kbuild test robot
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