Patch "ALSA: ump: Explicitly reset RPN with Null RPN" has been added to the 6.6-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    ALSA: ump: Explicitly reset RPN with Null RPN

to the 6.6-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-ump-explicitly-reset-rpn-with-null-rpn.patch
and it can be found in the queue-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 5db5dd74bbe2a385e417bb74f531b94994d1aa46
Author: Takashi Iwai <tiwai@xxxxxxx>
Date:   Wed Jul 31 15:05:23 2024 +0200

    ALSA: ump: Explicitly reset RPN with Null RPN
    
    [ Upstream commit 50a6dd19dca9446475f023eaa652016bfe5b1cbe ]
    
    RPN with 127:127 is treated as a Null RPN, just to reset the
    parameters, and it's not translated to MIDI2.  Although the current
    code can work as is in most cases, better to implement the RPN reset
    explicitly for Null message.
    
    Link: https://patch.msgid.link/20240731130528.12600-3-tiwai@xxxxxxx
    Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/sound/core/ump_convert.c b/sound/core/ump_convert.c
index 5d1b85e7ac165..0fe13d0316568 100644
--- a/sound/core/ump_convert.c
+++ b/sound/core/ump_convert.c
@@ -287,6 +287,15 @@ static int cvt_legacy_system_to_ump(struct ump_cvt_to_ump *cvt,
 	return 4;
 }
 
+static void reset_rpn(struct ump_cvt_to_ump_bank *cc)
+{
+	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;
+}
+
 static int fill_rpn(struct ump_cvt_to_ump_bank *cc,
 		    union snd_ump_midi2_msg *midi2,
 		    bool flush)
@@ -312,11 +321,7 @@ static int fill_rpn(struct ump_cvt_to_ump_bank *cc,
 	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;
+	reset_rpn(cc);
 	return 1;
 }
 
@@ -374,11 +379,15 @@ static int cvt_legacy_cmd_to_ump(struct ump_cvt_to_ump *cvt,
 			ret = fill_rpn(cc, midi2, true);
 			cc->rpn_set = 1;
 			cc->cc_rpn_msb = buf[2];
+			if (cc->cc_rpn_msb == 0x7f && cc->cc_rpn_lsb == 0x7f)
+				reset_rpn(cc);
 			return ret;
 		case UMP_CC_RPN_LSB:
 			ret = fill_rpn(cc, midi2, true);
 			cc->rpn_set = 1;
 			cc->cc_rpn_lsb = buf[2];
+			if (cc->cc_rpn_msb == 0x7f && cc->cc_rpn_lsb == 0x7f)
+				reset_rpn(cc);
 			return ret;
 		case UMP_CC_NRPN_MSB:
 			ret = fill_rpn(cc, midi2, true);