1 files changed, 46 insertions, 0 deletions

diff --git a/sound/usb/midi.c b/sound/usb/midi.c
index 7661616f3636..5b4c58c3e2c5 100644
--- a/sound/usb/midi.c
+++ b/sound/usb/midi.c
@@ -174,6 +174,8 @@ struct snd_usb_midi_in_endpoint {
                 u8 running_status_length;
         } ports[0x10];
         u8 seen_f5;
+        bool in_sysex;
+        u8 last_cin;
         u8 error_resubmit;
         int current_port;
 };
@@ -468,6 +470,39 @@ static void snd_usbmidi_maudio_broken_running_status_input(
 }
 
 /*
+ * QinHeng CH345 is buggy: every second packet inside a SysEx has not CIN 4
+ * but the previously seen CIN, but still with three data bytes.
+ */
+static void ch345_broken_sysex_input(struct snd_usb_midi_in_endpoint *ep,
+                                     uint8_t *buffer, int buffer_length)
+{
+        unsigned int i, cin, length;
+
+        for (i = 0; i + 3 < buffer_length; i += 4) {
+                if (buffer[i] == 0 && i > 0)
+                        break;
+                cin = buffer[i] & 0x0f;
+                if (ep->in_sysex &&
+                    cin == ep->last_cin &&
+                    (buffer[i + 1 + (cin == 0x6)] & 0x80) == 0)
+                        cin = 0x4;
+#if 0
+                if (buffer[i + 1] == 0x90) {
+                        /*
+                         * Either a corrupted running status or a real note-on
+                         * message; impossible to detect reliably.
+                         */
+                }
+#endif
+                length = snd_usbmidi_cin_length[cin];
+                snd_usbmidi_input_data(ep, 0, &buffer[i + 1], length);
+                ep->in_sysex = cin == 0x4;
+                if (!ep->in_sysex)
+                        ep->last_cin = cin;
+        }
+}
+
+/*
  * CME protocol: like the standard protocol, but SysEx commands are sent as a
  * single USB packet preceded by a 0x0F byte.
  */
@@ -660,6 +695,12 @@ static struct usb_protocol_ops snd_usbmidi_cme_ops = {
         .output_packet = snd_usbmidi_output_standard_packet,
 };
 
+static struct usb_protocol_ops snd_usbmidi_ch345_broken_sysex_ops = {
+        .input = ch345_broken_sysex_input,
+        .output = snd_usbmidi_standard_output,
+        .output_packet = snd_usbmidi_output_standard_packet,
+};
+
 /*
  * AKAI MPD16 protocol:
  *
@@ -1341,6 +1382,7 @@ static int snd_usbmidi_out_endpoint_create(struct snd_usb_midi *umidi,
                  * Various chips declare a packet size larger than 4 bytes, but
                  * do not actually work with larger packets:
                  */
+        case USB_ID(0x0a67, 0x5011): /* Medeli DD305 */
         case USB_ID(0x0a92, 0x1020): /* ESI M4U */
         case USB_ID(0x1430, 0x474b): /* RedOctane GH MIDI INTERFACE */
         case USB_ID(0x15ca, 0x0101): /* Textech USB Midi Cable */
@@ -2378,6 +2420,10 @@ int snd_usbmidi_create(struct snd_card *card,
 
                 err = snd_usbmidi_detect_per_port_endpoints(umidi, endpoints);
                 break;
+        case QUIRK_MIDI_CH345:
+                umidi->usb_protocol_ops = &snd_usbmidi_ch345_broken_sysex_ops;
+                err = snd_usbmidi_detect_per_port_endpoints(umidi, endpoints);
+                break;
         default:
                 dev_err(&umidi->dev->dev, "invalid quirk type %d\n",
                         quirk->type);