[PATCH v3 1/1] usb: xhci: apply XHCI_AVOID_BEI quirk to all Intel xHCI controllers

From: Lu Baolu
Date: Thu Mar 12 2015 - 20:54:45 EST

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@xxxxxxxxxxxxxxx>
Tested-by: Alistair Grant <akgrant0710@xxxxxxxxx>
Tested-by: Devin Heitmueller <dheitmueller@xxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
drivers/usb/host/xhci-pci.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

Change log:
v2: apply to all Intel xHC devices as suggested by Mathias
v3: add two Tested-by's

diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index fd53c9e..2af32e2 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -115,6 +115,7 @@ static void xhci_pci_quirks(struct device *dev, struct xhci_hcd *xhci)
if (pdev->vendor == PCI_VENDOR_ID_INTEL) {
xhci->quirks |= XHCI_LPM_SUPPORT;
xhci->quirks |= XHCI_INTEL_HOST;
+ xhci->quirks |= XHCI_AVOID_BEI;
if (pdev->vendor == PCI_VENDOR_ID_INTEL &&
@@ -130,7 +131,6 @@ static void xhci_pci_quirks(struct device *dev, struct xhci_hcd *xhci)
* PPT chipsets.
xhci->quirks |= XHCI_SPURIOUS_REBOOT;
- xhci->quirks |= XHCI_AVOID_BEI;
if (pdev->vendor == PCI_VENDOR_ID_INTEL &&

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