This is a note to let you know that I've just added the patch titled ALSA: line6: correct midi status byte when receiving data from podxt to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: alsa-line6-correct-midi-status-byte-when-receiving-data-from-podxt.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 8508fa2e7472f673edbeedf1b1d2b7a6bb898ecc Mon Sep 17 00:00:00 2001 From: Artem Egorkine <arteme@xxxxxxxxx> Date: Sun, 25 Dec 2022 12:57:27 +0200 Subject: ALSA: line6: correct midi status byte when receiving data from podxt From: Artem Egorkine <arteme@xxxxxxxxx> 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@xxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20221225105728.1153989-1-arteme@xxxxxxxxx Signed-off-by: Takashi Iwai <tiwai@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- sound/usb/line6/driver.c | 3 ++- sound/usb/line6/midi.c | 3 ++- sound/usb/line6/midibuf.c | 25 +++++++++++++++++-------- sound/usb/line6/midibuf.h | 5 ++++- sound/usb/line6/pod.c | 3 ++- 5 files changed, 27 insertions(+), 12 deletions(-) --- a/sound/usb/line6/driver.c +++ b/sound/usb/line6/driver.c @@ -304,7 +304,8 @@ static void line6_data_received(struct u 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; --- a/sound/usb/line6/midi.c +++ b/sound/usb/line6/midi.c @@ -60,7 +60,8 @@ static void line6_midi_transmit(struct s for (;;) { done = line6_midibuf_read(mb, chunk, - LINE6_FALLBACK_MAXPACKETSIZE); + LINE6_FALLBACK_MAXPACKETSIZE, + LINE6_MIDIBUF_READ_TX); if (done == 0) break; --- 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(unsign 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_buff } 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_buffe 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; --- 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 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); --- a/sound/usb/line6/pod.c +++ b/sound/usb/line6/pod.c @@ -169,8 +169,9 @@ static struct line6_pcm_properties pod_p .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: */ Patches currently in stable-queue which might be from arteme@xxxxxxxxx are queue-4.9/alsa-line6-fix-stack-overflow-in-line6_midi_transmit.patch queue-4.9/alsa-line6-correct-midi-status-byte-when-receiving-data-from-podxt.patch