ALSA: line6: correct midi status byte when receiving data from podxt
commit 8508fa2e7472f673edbeedf1b1d2b7a6bb898ecc upstream.
A PODxt device sends 0xb2, 0xc2 or 0xf2 as a status byte for MIDI
messages over USB that should otherwise have a 0xb0, 0xc0 or 0xf0
status byte. This is usually corrected by the driver on other OSes.
This fixes MIDI sysex messages sent by PODxt.
[ tiwai: fixed white spaces ]
Signed-off-by: Artem Egorkine <arteme@gmail.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20221225105728.1153989-1-arteme@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/sound/usb/line6/driver.c b/sound/usb/line6/driver.c
index c629a2b..b175da7 100644
--- a/sound/usb/line6/driver.c
+++ b/sound/usb/line6/driver.c
@@ -311,7 +311,8 @@ static void line6_data_received(struct urb *urb)
for (;;) {
done =
line6_midibuf_read(mb, line6->buffer_message,
- LINE6_MIDI_MESSAGE_MAXLEN);
+ LINE6_MIDI_MESSAGE_MAXLEN,
+ LINE6_MIDIBUF_READ_RX);
if (done <= 0)
break;
diff --git a/sound/usb/line6/midi.c b/sound/usb/line6/midi.c
index b5d62b5..8817667 100644
--- a/sound/usb/line6/midi.c
+++ b/sound/usb/line6/midi.c
@@ -60,7 +60,8 @@ static void line6_midi_transmit(struct snd_rawmidi_substream *substream)
for (;;) {
done = line6_midibuf_read(mb, chunk,
- LINE6_FALLBACK_MAXPACKETSIZE);
+ LINE6_FALLBACK_MAXPACKETSIZE,
+ LINE6_MIDIBUF_READ_TX);
if (done == 0)
break;
diff --git a/sound/usb/line6/midibuf.c b/sound/usb/line6/midibuf.c
index c931d48..4622234 100644
--- a/sound/usb/line6/midibuf.c
+++ b/sound/usb/line6/midibuf.c
@@ -13,6 +13,7 @@
#include "midibuf.h"
+
static int midibuf_message_length(unsigned char code)
{
int message_length;
@@ -24,12 +25,7 @@ static int midibuf_message_length(unsigned char code)
message_length = length[(code >> 4) - 8];
} else {
- /*
- Note that according to the MIDI specification 0xf2 is
- the "Song Position Pointer", but this is used by Line 6
- to send sysex messages to the host.
- */
- static const int length[] = { -1, 2, -1, 2, -1, -1, 1, 1, 1, 1,
+ static const int length[] = { -1, 2, 2, 2, -1, -1, 1, 1, 1, -1,
1, 1, 1, -1, 1, 1
};
message_length = length[code & 0x0f];
@@ -129,7 +125,7 @@ int line6_midibuf_write(struct midi_buffer *this, unsigned char *data,
}
int line6_midibuf_read(struct midi_buffer *this, unsigned char *data,
- int length)
+ int length, int read_type)
{
int bytes_used;
int length1, length2;
@@ -152,9 +148,22 @@ int line6_midibuf_read(struct midi_buffer *this, unsigned char *data,
length1 = this->size - this->pos_read;
- /* check MIDI command length */
command = this->buf[this->pos_read];
+ /*
+ PODxt always has status byte lower nibble set to 0010,
+ when it means to send 0000, so we correct if here so
+ that control/program changes come on channel 1 and
+ sysex message status byte is correct
+ */
+ if (read_type == LINE6_MIDIBUF_READ_RX) {
+ if (command == 0xb2 || command == 0xc2 || command == 0xf2) {
+ unsigned char fixed = command & 0xf0;
+ this->buf[this->pos_read] = fixed;
+ command = fixed;
+ }
+ }
+ /* check MIDI command length */
if (command & 0x80) {
midi_length = midibuf_message_length(command);
this->command_prev = command;
diff --git a/sound/usb/line6/midibuf.h b/sound/usb/line6/midibuf.h
index 6ea21ff..187f49c 100644
--- a/sound/usb/line6/midibuf.h
+++ b/sound/usb/line6/midibuf.h
@@ -12,6 +12,9 @@
#ifndef MIDIBUF_H
#define MIDIBUF_H
+#define LINE6_MIDIBUF_READ_TX 0
+#define LINE6_MIDIBUF_READ_RX 1
+
struct midi_buffer {
unsigned char *buf;
int size;
@@ -27,7 +30,7 @@ extern void line6_midibuf_destroy(struct midi_buffer *mb);
extern int line6_midibuf_ignore(struct midi_buffer *mb, int length);
extern int line6_midibuf_init(struct midi_buffer *mb, int size, int split);
extern int line6_midibuf_read(struct midi_buffer *mb, unsigned char *data,
- int length);
+ int length, int read_type);
extern void line6_midibuf_reset(struct midi_buffer *mb);
extern int line6_midibuf_write(struct midi_buffer *mb, unsigned char *data,
int length);
diff --git a/sound/usb/line6/pod.c b/sound/usb/line6/pod.c
index 73e6dc7..90ef623 100644
--- a/sound/usb/line6/pod.c
+++ b/sound/usb/line6/pod.c
@@ -169,8 +169,9 @@ static struct line6_pcm_properties pod_pcm_properties = {
.bytes_per_channel = 3 /* SNDRV_PCM_FMTBIT_S24_3LE */
};
+
static const char pod_version_header[] = {
- 0xf2, 0x7e, 0x7f, 0x06, 0x02
+ 0xf0, 0x7e, 0x7f, 0x06, 0x02
};
/* forward declarations: */