• Lu Baolu's avatar
    usb: xhci: apply XHCI_AVOID_BEI quirk to all Intel xHCI controllers · 227a4fd8
    Lu Baolu authored
    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 69e848c2 ("Intel xhci: Support EHCI/xHCI port switching.").
    Signed-off-by: default avatarLu Baolu <baolu.lu@linux.intel.com>
    Tested-by: default avatarAlistair Grant <akgrant0710@gmail.com>
    Cc: stable@vger.kernel.org
    Signed-off-by: default avatarMathias Nyman <mathias.nyman@linux.intel.com>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    227a4fd8
xhci-pci.c 11.8 KB