On Thu, 15 Mar 2012, Alex Shi wrote:
> USB3 requests line IRQ here but will disable it
> in later driver->start function and try MSI first.
>
> xhci_hcd 0000:02:00.0: irq 18, io mem 0xfe500000
> xhci_hcd 0000:02:00.0: irq 45 for MSI/MSI-X
> xhci_hcd 0000:02:00.0: irq 46 for MSI/MSI-X
>
> So it is better to remove the redundant request here. And
> save a little time in booting.
>
> Signed-off-by: Alex Shi <alex.shi@xxxxxxxxx>
> ---
> drivers/usb/core/hcd.c | 3 ++-
> 1 files changed, 2 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
> index e128232..5b09825 100644
> --- a/drivers/usb/core/hcd.c
> +++ b/drivers/usb/core/hcd.c
> @@ -2450,7 +2450,8 @@ int usb_add_hcd(struct usb_hcd *hcd,
> /* enable irqs just before we start the controller,
> * if the BIOS provides legacy PCI irqs.
> */
> - if (usb_hcd_is_primary_hcd(hcd) && irqnum) {
> + if (usb_hcd_is_primary_hcd(hcd) && irqnum
> + && (hcd->driver->flags & HCD_MASK) != HCD_USB3) {
> retval = usb_hcd_request_irqs(hcd, irqnum, irqflags);
> if (retval)
> goto err_request_irq;
This is not a good idea. What happens if some USB-3 controller
(perhaps a non-xHCI USB-3 controller) doesn't use MSI?
The right way to avoid registering a legacy interrupt handler is to
call usb_add_hcd() with irqnum equal to 0.
Alan Stern
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