path: root/drivers/usb/host/xhci-pci.c
diff options
authorSarah Sharp <sarah.a.sharp@linux.intel.com>2012-09-19 16:27:26 -0700
committerSarah Sharp <sarah.a.sharp@linux.intel.com>2012-09-25 15:19:34 -0700
commit80fab3b244a22e0ca539d2439bdda50e81e5666f (patch)
tree97fcf5110cd22e2ba6ff7776221192646915fc74 /drivers/usb/host/xhci-pci.c
parent457a73d346187c2cc5d599072f38676f18f130e0 (diff)
xhci: Intel Panther Point BEI quirk.
When a device with an isochronous endpoint is behind a hub plugged into the Intel Panther Point 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 a Panther Point xHCI host controller, if the parent hub is unplugged when one or more events from transfers with BEI set are on the event ring, a port status change event is placed on the event ring, but no interrupt is generated. This means URBs stop completing, and the USB device disconnect is not noticed. Something like a USB headset will cause mplayer to hang when the device is disconnected. If another transfer is sent (such as running `sudo lsusb -v`), the next transfer event seems to "unstick" the event ring, the xHCI driver gets an interrupt, and the disconnect is reported to the USB core. The fix is not to use the BEI flag under the Panther Point xHCI host. This will impact power consumption and system responsiveness, because the xHCI driver will receive an interrupt for every frame in all isochronous URBs instead of once per URB. Intel chipset developers confirm that this bug will be hit if the BEI flag is used on any endpoint, not just ones that are behind a hub. This patch should be backported to kernels as old as 3.0, that contain the commit 69e848c2090aebba5698a1620604c7dccb448684 "Intel xhci: Support EHCI/xHCI port switching." Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Cc: stable@vger.kernel.org
Diffstat (limited to 'drivers/usb/host/xhci-pci.c')
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index 9bfd4ca1153c..8345d7c23061 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -103,6 +103,7 @@ 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_ETRON &&
pdev->device == PCI_DEVICE_ID_ASROCK_P67) {