patch "usb: Use the USB_SS_MULT() macro to get the burst multiplier." added to usb-linus

This is a note to let you know that I've just added the patch titled

usb: Use the USB_SS_MULT() macro to get the burst multiplier.

to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From: Mathias Nyman <[email protected]>
Date: Mon, 21 Sep 2015 17:46:09 +0300
Subject: usb: Use the USB_SS_MULT() macro to get the burst multiplier.

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.

---
 drivers/usb/core/config.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

index b2a540b43f97..b9ddf0c1ffe5 100644
@@ -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) *

2.5.3