From d05cc104320210e1c38ff9675c5038cffb2d86dc Mon Sep 17 00:00:00 2001 From: Clemens Ladisch Date: Mon, 7 May 2007 09:28:53 +0200 Subject: [ALSA] usb-audio: work around broken M-Audio MidiSport Uno firmware The firmware of the M-Audio USB Uno MIDI Interface has, at least in hardware revision 1.25, a bug that garbles its USB output. When it receives a Note On MIDI message that uses running status, the resulting USB MIDI packet has a wrong CIN (4 instead of 9) and a wrong length (2 bytes, the status byte is still missing). This patch adds a workaround to track the CINs and the MIDI messages of received USB MIDI packets to detect whether a packet with CIN 4 is a correct SysEx packet or a buggy running status packet. Signed-off-by: Clemens Ladisch Signed-off-by: Jaroslav Kysela --- sound/usb/usbmidi.c | 52 +++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 51 insertions(+), 1 deletion(-) (limited to 'sound') diff --git a/sound/usb/usbmidi.c b/sound/usb/usbmidi.c index 24f5a26c5f0..911f4482b5e 100644 --- a/sound/usb/usbmidi.c +++ b/sound/usb/usbmidi.c @@ -1,7 +1,7 @@ /* * usbmidi.c - ALSA USB MIDI driver * - * Copyright (c) 2002-2005 Clemens Ladisch + * Copyright (c) 2002-2007 Clemens Ladisch * All rights reserved. * * Based on the OSS usb-midi driver by NAGANO Daisuke, @@ -145,6 +145,7 @@ struct snd_usb_midi_in_endpoint { struct urb* urb; struct usbmidi_in_port { struct snd_rawmidi_substream *substream; + u8 running_status_length; } ports[0x10]; u8 seen_f5; u8 error_resubmit; @@ -365,6 +366,46 @@ static void snd_usbmidi_midiman_input(struct snd_usb_midi_in_endpoint* ep, } } +/* + * Buggy M-Audio device: running status on input results in a packet that has + * the data bytes but not the status byte and that is marked with CIN 4. + */ +static void snd_usbmidi_maudio_broken_running_status_input( + struct snd_usb_midi_in_endpoint* ep, + uint8_t* buffer, int buffer_length) +{ + int i; + + for (i = 0; i + 3 < buffer_length; i += 4) + if (buffer[i] != 0) { + int cable = buffer[i] >> 4; + u8 cin = buffer[i] & 0x0f; + struct usbmidi_in_port *port = &ep->ports[cable]; + int length; + + length = snd_usbmidi_cin_length[cin]; + if (cin == 0xf && buffer[i + 1] >= 0xf8) + ; /* realtime msg: no running status change */ + else if (cin >= 0x8 && cin <= 0xe) + /* channel msg */ + port->running_status_length = length - 1; + else if (cin == 0x4 && + port->running_status_length != 0 && + buffer[i + 1] < 0x80) + /* CIN 4 that is not a SysEx */ + length = port->running_status_length; + else + /* + * All other msgs cannot begin running status. + * (A channel msg sent as two or three CIN 0xF + * packets could in theory, but this device + * doesn't use this format.) + */ + port->running_status_length = 0; + snd_usbmidi_input_data(ep, cable, &buffer[i + 1], length); + } +} + /* * Adds one USB MIDI packet to the output buffer. */ @@ -525,6 +566,12 @@ static struct usb_protocol_ops snd_usbmidi_midiman_ops = { .output_packet = snd_usbmidi_output_midiman_packet, }; +static struct usb_protocol_ops snd_usbmidi_maudio_broken_running_status_ops = { + .input = snd_usbmidi_maudio_broken_running_status_input, + .output = snd_usbmidi_standard_output, + .output_packet = snd_usbmidi_output_standard_packet, +}; + /* * Novation USB MIDI protocol: number of data bytes is in the first byte * (when receiving) (+1!) or in the second byte (when sending); data begins @@ -1606,6 +1653,9 @@ int snd_usb_create_midi_interface(struct snd_usb_audio* chip, switch (quirk ? quirk->type : QUIRK_MIDI_STANDARD_INTERFACE) { case QUIRK_MIDI_STANDARD_INTERFACE: err = snd_usbmidi_get_ms_info(umidi, endpoints); + if (chip->usb_id == USB_ID(0x0763, 0x0150)) /* M-Audio Uno */ + umidi->usb_protocol_ops = + &snd_usbmidi_maudio_broken_running_status_ops; break; case QUIRK_MIDI_FIXED_ENDPOINT: memcpy(&endpoints[0], quirk->data, -- cgit v1.2.3