usb: gadget: f_midi: Fixed a bug when buflen was smaller than wMaxPacketSize

[ Upstream commit 03d27ade4941076b34c823d63d91dc895731a595 ]

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>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>

diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c
index 6316aa5b1c4947a6df2e08b4c45856dc77b94374..d97f362b360479d1b9cc808332d1e97bb0927840 100644 (file)
--- a/drivers/usb/gadget/function/f_midi.c
+++ b/drivers/usb/gadget/function/f_midi.c
@@ -359,7 +359,9 @@ static int f_midi_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
        /* 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;