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

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>

diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c
index 56e2dde99b03435cfd0761c7222eb8241ebd1e41..9ad51dcab98249b361a9b9005878d88a6f3f1890 100644 (file)
--- a/drivers/usb/gadget/function/f_midi.c
+++ b/drivers/usb/gadget/function/f_midi.c
@@ -360,7 +360,9 @@ 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;