[PATCH 3.19.y-ckt 46/86] usb: Use the USB_SS_MULT() macro to get the burst multiplier.

[Kamal Mostafa]

3.19.8-ckt9 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Mathias Nyman <mathias.nyman at linux.intel.com>

commit ff30cbc8da425754e8ab96904db1d295bd034f27 upstream.

Bits 1:0 of the bmAttributes are used for the burst multiplier.
The rest of the bits used to be reserved (zero), but USB3.1 takes bit 7
into use.

Use the existing USB_SS_MULT() macro instead to make sure the mult value
and hence max packet calculations are correct for USB3.1 devices.

Note that burst multiplier in bmAttributes is zero based and that
the USB_SS_MULT() macro adds one.

Signed-off-by: Mathias Nyman <mathias.nyman at linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/usb/core/config.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/core/config.c b/drivers/usb/core/config.c
index b2a540b..b9ddf0c 100644
--- a/drivers/usb/core/config.c
+++ b/drivers/usb/core/config.c
@@ -112,7 +112,7 @@ static void usb_parse_ss_endpoint_companion(struct device *ddev, int cfgno,
 				cfgno, inum, asnum, ep->desc.bEndpointAddress);
 		ep->ss_ep_comp.bmAttributes = 16;
 	} else if (usb_endpoint_xfer_isoc(&ep->desc) &&
-			desc->bmAttributes > 2) {
+		   USB_SS_MULT(desc->bmAttributes) > 3) {
 		dev_warn(ddev, "Isoc endpoint has Mult of %d in "
 				"config %d interface %d altsetting %d ep %d: "
 				"setting to 3\n", desc->bmAttributes + 1,
@@ -121,7 +121,8 @@ static void usb_parse_ss_endpoint_companion(struct device *ddev, int cfgno,
 	}
 
 	if (usb_endpoint_xfer_isoc(&ep->desc))
-		max_tx = (desc->bMaxBurst + 1) * (desc->bmAttributes + 1) *
+		max_tx = (desc->bMaxBurst + 1) *
+			(USB_SS_MULT(desc->bmAttributes)) *
 			usb_endpoint_maxp(&ep->desc);
 	else if (usb_endpoint_xfer_int(&ep->desc))
 		max_tx = usb_endpoint_maxp(&ep->desc) *
-- 
1.9.1