linux-kernel - [PATCH 3.10 050/268] usb: gadget: composite: always set ep->mult to a sensible value

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Date:   Mon, 19 Jun 2017 20:29:09 +0200
From:   Willy Tarreau <w@....eu>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        linux@...ck-us.net
Cc:     Felipe Balbi <felipe.balbi@...ux.intel.com>,
        Willy Tarreau <w@....eu>
Subject: [PATCH 3.10 050/268] usb: gadget: composite: always set ep->mult to a sensible value

From: Felipe Balbi <felipe.balbi@...ux.intel.com>

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.

Signed-off-by: Felipe Balbi <felipe.balbi@...ux.intel.com>
Signed-off-by: Willy Tarreau <w@....eu>
---
 drivers/usb/gadget/composite.c | 9 +++++++--
 drivers/usb/gadget/uvc_video.c | 2 +-
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index 584e43c..00c03c7 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -129,7 +129,12 @@ 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(_ep->desc) & 0x1800) >> 11) + 1;
+
 	if (!want_comp_desc)
 		return 0;
 
@@ -146,7 +151,7 @@ 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;
diff --git a/drivers/usb/gadget/uvc_video.c b/drivers/usb/gadget/uvc_video.c
index 71e896d..43e8c65 100644
--- a/drivers/usb/gadget/uvc_video.c
+++ b/drivers/usb/gadget/uvc_video.c
@@ -240,7 +240,7 @@ uvc_video_alloc_requests(struct uvc_video *video)
 
 	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);
-- 
2.8.0.rc2.1.gbe9624a