From: Dmitry Torokhov <dtor@xxxxxxxxxx> Full-speed isoc endpoints specify interval in exponent based form in frames, not microframes, so we need to adjust accordingly. NEC xHCI host controllers will return an error code of 0x11 if a full speed isochronous endpoint is added with the Interval field set to something less than 3 (2^3 = 8 microframes, or one frame). It is impossible for a full speed device to have an interval smaller than one frame. This was always an issue in the xHCI driver, but commit dfa49c4ad120a784ef1ff0717168aa79f55a483a "USB: xhci - fix math in xhci_get_endpoint_interval()" removed the clamping of the minimum value in the Interval field, which revealed this bug. This needs to be backported to stable kernels back to 2.6.31. Reported-by: Matt Evans <matt@xxxxxxxxxx> Signed-off-by: Dmitry Torokhov <dtor@xxxxxxxxxx> Signed-off-by: Sarah Sharp <sarah.a.sharp@xxxxxxxxxxxxxxx> --- drivers/usb/host/xhci-mem.c | 14 ++++++++++++-- 1 files changed, 12 insertions(+), 2 deletions(-) diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c index 26caba4..0f8e1d2 100644 --- a/drivers/usb/host/xhci-mem.c +++ b/drivers/usb/host/xhci-mem.c @@ -985,9 +985,19 @@ static unsigned int xhci_parse_exponent_interval(struct usb_device *udev, interval = clamp_val(ep->desc.bInterval, 1, 16) - 1; if (interval != ep->desc.bInterval - 1) dev_warn(&udev->dev, - "ep %#x - rounding interval to %d microframes\n", + "ep %#x - rounding interval to %d %sframes\n", ep->desc.bEndpointAddress, - 1 << interval); + 1 << interval, + udev->speed == USB_SPEED_FULL ? "" : "micro"); + + if (udev->speed == USB_SPEED_FULL) { + /* + * Full speed isoc endpoints specify interval in frames, + * not microframes. We are using microframes everywhere, + * so adjust accordingly. + */ + interval += 3; /* 1 frame = 2^3 uframes */ + } return interval; } -- 1.7.4.1 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html