[PATCH 3.16 012/370] usb: gadget: composite: correctly initialize ep->maxpacket

Ben Hutchings
2017-03-10T14:12:33Z

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

commit e8f29bb719b47a234f33b0af62974d7a9521a52c upstream.

usb_endpoint_maxp() returns wMaxPacketSize in its
raw form. Without taking into consideration that it
also contains other bits reserved for isochronous
endpoints.

This patch fixes one occasion where this is a
problem by making sure that we initialize
ep->maxpacket only with lower 10 bits of the value
returned by usb_endpoint_maxp(). Note that seperate
patches will be necessary to audit all call sites of
usb_endpoint_maxp() and make sure that
usb_endpoint_maxp() only returns lower 10 bits of
wMaxPacketSize.

Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/usb/gadget/composite.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -143,7 +143,7 @@ int config_ep_by_speed(struct usb_gadget

ep_found:
/* commit results */
- _ep->maxpacket = usb_endpoint_maxp(chosen_desc);
+ _ep->maxpacket = usb_endpoint_maxp(chosen_desc) & 0x7ff;
_ep->desc = chosen_desc;
_ep->comp_desc = NULL;
_ep->maxburst = 0;