Patch "usb: gadget: composite: always set ep->mult to a sensible value" has been added to the 4.8-stable tree

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

    usb: gadget: composite: always set ep->mult to a sensible value

to the 4.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
usb-gadget-composite-always-set-ep-mult-to-a-sensible-value.patch
and it can be found in the queue-4.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Felipe Balbi <[email protected]>
Date: Wed, 28 Sep 2016 12:33:31 +0300
Subject: usb: gadget: composite: always set ep->mult to a sensible value

From: Felipe Balbi <[email protected]>

commit eaa496ffaaf19591fe471a36cef366146eeb9153 upstream.

ep->mult is supposed to be set to Isochronous and Interrupt Endapoint's multiplier value. This value is computed from different places depending on the link speed.

If we're dealing with HighSpeed, then it's part of bits [12:11] of wMaxPacketSize. This case wasn't taken into consideration before.

While at that, also make sure the ep->mult defaults to one so drivers can use it unconditionally and assume they'll never multiply ep->maxpacket to zero.

---
 drivers/usb/gadget/composite.c          |    9 +++++++--
 drivers/usb/gadget/function/uvc_video.c |    2 +-
 2 files changed, 8 insertions(+), 3 deletions(-)

@@ -201,7 +201,12 @@ ep_found:
 	_ep->desc = chosen_desc;
 	_ep->comp_desc = NULL;
 	_ep->maxburst = 0;
-	_ep->mult = 0;
+	_ep->mult = 1;
+
+	if (g->speed == USB_SPEED_HIGH && (usb_endpoint_xfer_isoc(_ep->desc) ||
+				usb_endpoint_xfer_int(_ep->desc)))
+		_ep->mult = usb_endpoint_maxp_mult(_ep->desc);
+
 	if (!want_comp_desc)
 		return 0;
 

@@ -218,7 +223,7 @@ ep_found:
 		switch (usb_endpoint_type(_ep->desc)) {
 		case USB_ENDPOINT_XFER_ISOC:
 			/* mult: bits 1:0 of bmAttributes */
-			_ep->mult = comp_desc->bmAttributes & 0x3;
+			_ep->mult = (comp_desc->bmAttributes & 0x3) + 1;
 		case USB_ENDPOINT_XFER_BULK:
 		case USB_ENDPOINT_XFER_INT:
 			_ep->maxburst = comp_desc->bMaxBurst + 1;

@@ -243,7 +243,7 @@ uvc_video_alloc_requests(struct uvc_vide
 
 	req_size = video->ep->maxpacket
 		 * max_t(unsigned int, video->ep->maxburst, 1)
-		 * (video->ep->mult + 1);
+		 * (video->ep->mult);
 
 	for (i = 0; i < UVC_NUM_REQUESTS; ++i) {
 		video->req_buffer[i] = kmalloc(req_size, GFP_KERNEL);

Patches currently in stable-queue which might be from [email protected] are

queue-4.8/usb-gadget-composite-always-set-ep-mult-to-a-sensible-value.patch queue-4.8/usb-gadget-f_uac2-fix-error-handling-at-afunc_bind.patch queue-4.8/usb-dwc3-gadget-set-pcm1-field-of-isochronous-first-trbs.patch queue-4.8/usb-gadget-composite-correctly-initialize-ep-maxpacket.patch