On Thu, 23 Dec 2010, Sarah Sharp wrote:
> > Then instead of guessing about whether or not pdev->irq should be the
> > same as hcd->irq, and what it might mean if they are different, just
> > add a new "don't synchronize irqs" flag to the usb_hcd structure.
>
> Like so?
>
> diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c
> index 3799573..da9d96d 100644
> --- a/drivers/usb/core/hcd-pci.c
> +++ b/drivers/usb/core/hcd-pci.c
> @@ -406,7 +406,12 @@ static int suspend_common(struct device *dev, bool do_wakeup)
> return retval;
> }
>
> - synchronize_irq(pci_dev->irq);
> + /* If MSI-X is enabled, the driver will have synchronized all vectors in
> + * pci_suspend(). If MSI or legacy PCI is enabled, that will be
> + * synchronized here.
> + */
> + if (!HCD_MSIX_ENABLED(hcd))
> + synchronize_irq(pci_dev->irq);
> diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h
> index 0b6e751..d9a8983 100644
> --- a/include/linux/usb/hcd.h
> +++ b/include/linux/usb/hcd.h
> @@ -99,6 +99,7 @@ struct usb_hcd {
> #define HCD_FLAG_POLL_RH 2 /* poll for rh status? */
> #define HCD_FLAG_POLL_PENDING 3 /* status has changed? */
> #define HCD_FLAG_WAKEUP_PENDING 4 /* root hub is resuming? */
> +#define HCD_FLAG_MSIX 5 /* driver has MSI-X enabled? */
>
> /* The flags can be tested using these macros; they are likely to
> * be slightly faster than test_bit().
> @@ -108,6 +109,7 @@ struct usb_hcd {
> #define HCD_POLL_RH(hcd) ((hcd)->flags & (1U << HCD_FLAG_POLL_RH))
> #define HCD_POLL_PENDING(hcd) ((hcd)->flags & (1U << HCD_FLAG_POLL_PENDING))
> #define HCD_WAKEUP_PENDING(hcd) ((hcd)->flags & (1U << HCD_FLAG_WAKEUP_PENDING))
> +#define HCD_MSIX_ENABLED(hcd) ((hcd)->flags & (1U << HCD_FLAG_MSIX))
>
> /* Flags that get set only during HCD registration or removal. */
> unsigned rh_registered:1;/* is root hub registered? */
Exactly. Except that since this flag gets set only when the driver is
probed, you can use a regular bitflag (like rh_registered above)
instead of an atomic bitflag. Right? I assume you don't turn MSI-X
on and off dynamically while things are running.
Alan Stern
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