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

From: David Härdeman
Date: Fri Mar 01 2013 - 05:54:02 EST


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@xxxxxxxxxx>
>Cc: Oliver Neukum <oneukum@xxxxxxx>
>Cc: Thomas Renninger <trenn@xxxxxxx>
>Cc: Yinghai Lu <yinghai@xxxxxxxxxx>
>Cc: Frederik Himpe <fhimpe@xxxxxxxxx>
>Cc: David Haerdeman <david@xxxxxxxxxxx>
>Signed-off-by: Hannes Reinecke <hare@xxxxxxx>

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

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