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>

1 files changed, 9 insertions, 2 deletions

diff --git a/sound/usb/midi.c b/sound/usb/midi.c
index d7021cb01047..db2dc5ffe6dd 100644
--- 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,