[4.4,14/43] usb: gadget: f_midi: Fixed a bug when buflen was smaller than wMaxPacketSize
diff mbox series

Message ID 20170501212600.104433199@linuxfoundation.org
State New, archived
Headers show
Series
  • 4.4.66-stable review
Related show

Commit Message

Greg KH May 1, 2017, 9:27 p.m. UTC
4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Felipe F. Tonello <eu@felipetonello.com>

commit 03d27ade4941076b34c823d63d91dc895731a595 upstream.

buflen by default (256) is smaller than wMaxPacketSize (512) in high-speed
devices.

That caused the OUT endpoint to freeze if the host send any data packet of
length greater than 256 bytes.

This is an example dump of what happended on that enpoint:
HOST:   [DATA][Length=260][...]
DEVICE: [NAK]
HOST:   [PING]
DEVICE: [NAK]
HOST:   [PING]
DEVICE: [NAK]
...
HOST:   [PING]
DEVICE: [NAK]

This patch fixes this problem by setting the minimum usb_request's buffer size
for the OUT endpoint as its wMaxPacketSize.

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Felipe F. Tonello <eu@felipetonello.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Cc: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/usb/gadget/function/f_midi.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Patch
diff mbox series

--- a/drivers/usb/gadget/function/f_midi.c
+++ b/drivers/usb/gadget/function/f_midi.c
@@ -361,7 +361,9 @@  static int f_midi_set_alt(struct usb_fun
 	/* allocate a bunch of read buffers and queue them all at once. */
 	for (i = 0; i < midi->qlen && err == 0; i++) {
 		struct usb_request *req =
-			midi_alloc_ep_req(midi->out_ep, midi->buflen);
+			midi_alloc_ep_req(midi->out_ep,
+				max_t(unsigned, midi->buflen,
+					bulk_out_desc.wMaxPacketSize));
 		if (req == NULL)
 			return -ENOMEM;