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authorDmitry Torokhov <dtor@vmware.com>2011-05-31 14:37:23 -0700
committerGreg Kroah-Hartman <gregkh@suse.de>2011-06-23 15:24:07 -0700
commite103cc4da54d55dfcd6d82bf923f578ebc5b9425 (patch)
tree77968e4b68a7cd89437b0c8629ed862e6b8e137e /drivers
parent68fdcd2a5855fde5c9322b378a699d4bd6877e48 (diff)
downloadlinux-linaro-stable-e103cc4da54d55dfcd6d82bf923f578ebc5b9425.tar.gz
USB: xhci - fix interval calculation for FS isoc endpoints
commit cd3c18ba2fac14b34d03cae111f215009735ea06 upstream. 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@ozlabs.org> Signed-off-by: Dmitry Torokhov <dtor@vmware.com> Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/usb/host/xhci-mem.c14
1 files changed, 12 insertions, 2 deletions
diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index 75f211532cf6..fce7b5e1d39e 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -452,9 +452,19 @@ 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;
}