Re: [PATCH] usb: correctly enable interrupts for xhci

["David Härdeman" <david@hardeman.nu>]

On Fri, Mar 01, 2013 at 09:52:54AM +0100, Hannes Reinecke wrote:
>xhci might run with MSI/MSI-X only, with no support for legacy
>interrupts. On these devices the request_irq() call in usb_add_hcd()
>will fail, causing the entire device to fail.
>For xhci this is especially painful as the driver will enable
>interrupts during xhci_run(), so the initial call to request_irq()
>is not required anyway.
>
>This patch adds a flag 'msix_supported' to struct usb_hcd, which
>will cause usb_add_hcd() to skip interrupt setup. This flag is
>set in xhci-pci, so the registration will skip the first request_irq()
>and can proceed.
>
>Cc: Bjorn Helgaas <bhelgaas@google.com>
>Cc: Oliver Neukum <oneukum@suse.de>
>Cc: Thomas Renninger <trenn@suse.de>
>Cc: Yinghai Lu <yinghai@kernel.org>
>Cc: Frederik Himpe <fhimpe@vub.ac.be>
>Cc: David Haerdeman <david@hardeman.nu>
>Signed-off-by: Hannes Reinecke <hare@suse.de>

It doesn't seem to work. I just tried applying the patch to the 3.8
kernel in Debian experimental and this was the result during boot:

[    1.203390] xhci_hcd 0000:00:14.0: can't derive routing for PCI INT A
[    1.203393] xhci_hcd 0000:00:14.0: PCI INT A: no GSI
[    1.203419] xhci_hcd 0000:00:14.0: setting latency timer to 64
[    1.203423] xhci_hcd 0000:00:14.0: xHCI Host Controller
[    1.203429] xhci_hcd 0000:00:14.0: new USB bus registered, assigned bus number 1
[    1.203533] xhci_hcd 0000:00:14.0: cache line size of 64 is not supported
[    1.203535] xhci_hcd 0000:00:14.0: request interrupt 255 failed
[    1.203580] xhci_hcd 0000:00:14.0: USB bus 1 deregistered
[    1.203598] xhci_hcd 0000:00:14.0: can't derive routing for PCI INT A
[    1.203600] xhci_hcd 0000:00:14.0: init 0000:00:14.0 fail, -22
[    1.203643] xhci_hcd: probe of 0000:00:14.0 failed with error -22

Regards,
David