tree 9c4c585d26e2d167b471708c72f942041c718f56
parent 9425183d177aa4a2f09d01a74925124f0778b595
author Lu Baolu <baolu.lu@linux.intel.com> 1427128062 +0200
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1427143872 +0100

usb: xhci: apply XHCI_AVOID_BEI quirk to all Intel xHCI controllers

When a device with an isochronous endpoint is plugged into the Intel
xHCI host controller, and the driver submits multiple frames per URB,
the xHCI driver will set the Block Event Interrupt (BEI) flag on all
but the last TD for the URB. This causes the host controller to place
an event on the event ring, but not send an interrupt. When the last
TD for the URB completes, BEI is cleared, and we get an interrupt for
the whole URB.

However, under Intel xHCI host controllers, if the event ring is full
of events from transfers with BEI set,  an "Event Ring is Full" event
will be posted to the last entry of the event ring,  but no interrupt
is generated. Host will cease all transfer and command executions and
wait until software completes handling the pending events in the event
ring.  That means xHC stops, but event of "event ring is full" is not
notified. As the result, the xHC looks like dead to user.

This patch is to apply XHCI_AVOID_BEI quirk to Intel xHC devices. And
it should be backported to kernels as old as 3.0, that contains the
commit 69e848c2090a ("Intel xhci: Support EHCI/xHCI port switching.").

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Tested-by: Alistair Grant <akgrant0710@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>