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usb: gadget: composite: always set ep->mult to a sensible value
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commit eaa496f 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.

Cc: <stable@vger.kernel.org>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Felipe Balbi authored and Greg Kroah-Hartman committed Jan 6, 2017
1 parent b35f34f commit c53af76
Showing 2 changed files with 8 additions and 3 deletions.
9 changes: 7 additions & 2 deletions drivers/usb/gadget/composite.c
Original file line number Diff line number Diff line change
@@ -148,7 +148,12 @@ int config_ep_by_speed(struct usb_gadget *g,
_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) & 0x7ff;

if (!want_comp_desc)
return 0;

@@ -165,7 +170,7 @@ int config_ep_by_speed(struct usb_gadget *g,
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;
2 changes: 1 addition & 1 deletion drivers/usb/gadget/function/uvc_video.c
Original file line number Diff line number Diff line change
@@ -243,7 +243,7 @@ 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);

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