Commit e6ce8a28 authored by Takashi Iwai's avatar Takashi Iwai
Browse files

ALSA: ump: Transmit RPN/NRPN message at each MSB/LSB data reception 

The UMP 1.1 spec says that an RPN/NRPN should be sent when one of the
following occurs:
* a CC 38 is received
* a subsequent CC 6 is received
* a CC 98, 99, 100, and 101 is received, indicating the last RPN/NRPN
  message has ended and a new one has started

That said, we should send a partial data even if it's not fully
filled.  Let's change the UMP conversion helper code to follow that
rule.

Link: https://patch.msgid.link/20240731130528.12600-2-tiwai@suse.de


Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 3dab73ab

include/sound/ump_convert.h

+1 −0
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ struct ump_cvt_to_ump_bank { 
	unsigned char cc_nrpn_msb, cc_nrpn_lsb;

	unsigned char cc_data_msb, cc_data_lsb;

	unsigned char cc_bank_msb, cc_bank_lsb;

	bool cc_data_msb_set, cc_data_lsb_set;

};



/* context for converting from MIDI1 byte stream to UMP packet */

sound/core/ump_convert.c

+32 −17
Original line number Diff line number Diff line
@@ -287,25 +287,37 @@ static int cvt_legacy_system_to_ump(struct ump_cvt_to_ump *cvt, 
	return 4;

}



static void fill_rpn(struct ump_cvt_to_ump_bank *cc,

		     union snd_ump_midi2_msg *midi2)

static int fill_rpn(struct ump_cvt_to_ump_bank *cc,

		    union snd_ump_midi2_msg *midi2,

		    bool flush)

{

	if (!(cc->cc_data_lsb_set || cc->cc_data_msb_set))

		return 0; // skip

	/* when not flushing, wait for complete data set */

	if (!flush && (!cc->cc_data_lsb_set || !cc->cc_data_msb_set))

		return 0; // skip



	if (cc->rpn_set) {

		midi2->rpn.status = UMP_MSG_STATUS_RPN;

		midi2->rpn.bank = cc->cc_rpn_msb;

		midi2->rpn.index = cc->cc_rpn_lsb;

		cc->rpn_set = 0;

		cc->cc_rpn_msb = cc->cc_rpn_lsb = 0;

	} else {

	} else if (cc->nrpn_set) {

		midi2->rpn.status = UMP_MSG_STATUS_NRPN;

		midi2->rpn.bank = cc->cc_nrpn_msb;

		midi2->rpn.index = cc->cc_nrpn_lsb;

		cc->nrpn_set = 0;

		cc->cc_nrpn_msb = cc->cc_nrpn_lsb = 0;

	} else {

		return 0; // skip

	}



	midi2->rpn.data = upscale_14_to_32bit((cc->cc_data_msb << 7) |

					      cc->cc_data_lsb);



	cc->rpn_set = 0;

	cc->nrpn_set = 0;

	cc->cc_rpn_msb = cc->cc_rpn_lsb = 0;

	cc->cc_data_msb = cc->cc_data_lsb = 0;

	cc->cc_data_msb_set = cc->cc_data_lsb_set = 0;

	return 1;

}



/* convert to a MIDI 1.0 Channel Voice message */
@@ -318,6 +330,7 @@ static int cvt_legacy_cmd_to_ump(struct ump_cvt_to_ump *cvt, 
	struct ump_cvt_to_ump_bank *cc;

	union snd_ump_midi2_msg *midi2 = (union snd_ump_midi2_msg *)data;

	unsigned char status, channel;

	int ret;



	BUILD_BUG_ON(sizeof(union snd_ump_midi1_msg) != 4);

	BUILD_BUG_ON(sizeof(union snd_ump_midi2_msg) != 8);
@@ -358,24 +371,29 @@ static int cvt_legacy_cmd_to_ump(struct ump_cvt_to_ump *cvt, 
	case UMP_MSG_STATUS_CC:

		switch (buf[1]) {

		case UMP_CC_RPN_MSB:

			ret = fill_rpn(cc, midi2, true);

			cc->rpn_set = 1;

			cc->cc_rpn_msb = buf[2];

			return 0; // skip

			return ret;

		case UMP_CC_RPN_LSB:

			ret = fill_rpn(cc, midi2, true);

			cc->rpn_set = 1;

			cc->cc_rpn_lsb = buf[2];

			return 0; // skip

			return ret;

		case UMP_CC_NRPN_MSB:

			ret = fill_rpn(cc, midi2, true);

			cc->nrpn_set = 1;

			cc->cc_nrpn_msb = buf[2];

			return 0; // skip

			return ret;

		case UMP_CC_NRPN_LSB:

			ret = fill_rpn(cc, midi2, true);

			cc->nrpn_set = 1;

			cc->cc_nrpn_lsb = buf[2];

			return 0; // skip

			return ret;

		case UMP_CC_DATA:

			cc->cc_data_msb_set = 1;

			cc->cc_data_msb = buf[2];

			return 0; // skip

			return fill_rpn(cc, midi2, false);

		case UMP_CC_BANK_SELECT:

			cc->bank_set = 1;

			cc->cc_bank_msb = buf[2];
@@ -385,12 +403,9 @@ static int cvt_legacy_cmd_to_ump(struct ump_cvt_to_ump *cvt, 
			cc->cc_bank_lsb = buf[2];

			return 0; // skip

		case UMP_CC_DATA_LSB:

			cc->cc_data_lsb_set = 1;

			cc->cc_data_lsb = buf[2];

			if (cc->rpn_set || cc->nrpn_set)

				fill_rpn(cc, midi2);

			else

				return 0; // skip

			break;

			return fill_rpn(cc, midi2, false);

		default:

			midi2->cc.index = buf[1];

			midi2->cc.data = upscale_7_to_32bit(buf[2]);