ALSA: snd-usb-us122l: Fix MIDI output

The US-122L always reads 9 bytes per urb unless they are set to 0xFD.

Signed-off-by: Karsten Wiese <fzu@wemgehoertderstaat.de>
Cc: stable@kernel.org
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/usb/midi.c b/sound/usb/midi.c
index d7021cb..db2dc5f 100644 (file)
--- a/sound/usb/midi.c
+++ b/sound/usb/midi.c
@@ -850,8 +850,8 @@ static void snd_usbmidi_us122l_output(struct snd_usb_midi_out_endpoint *ep,
                return;
        }
 
-       memset(urb->transfer_buffer + count, 0xFD, 9 - count);
-       urb->transfer_buffer_length = count;
+       memset(urb->transfer_buffer + count, 0xFD, ep->max_transfer - count);
+       urb->transfer_buffer_length = ep->max_transfer;
 }
 
 static struct usb_protocol_ops snd_usbmidi_122l_ops = {
@@ -1295,6 +1295,13 @@ static int snd_usbmidi_out_endpoint_create(struct snd_usb_midi* umidi,
        case USB_ID(0x1a86, 0x752d): /* QinHeng CH345 "USB2.0-MIDI" */
                ep->max_transfer = 4;
                break;
+               /*
+                * Some devices only work with 9 bytes packet size:
+                */
+       case USB_ID(0x0644, 0x800E): /* Tascam US-122L */
+       case USB_ID(0x0644, 0x800F): /* Tascam US-144 */
+               ep->max_transfer = 9;
+               break;
        }
        for (i = 0; i < OUTPUT_URBS; ++i) {
                buffer = usb_alloc_coherent(umidi->dev,