usb: gadget: composite: correctly initialize ep->maxpacket

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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index 8b14c2a13ac51abc9d3f433a0261c599ec8cdaf6..e9bc1d392783e5982de97bf0a1e0519344c8544e 100644 (file)
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -144,7 +144,7 @@ int config_ep_by_speed(struct usb_gadget *g,
 
 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;