From 6fe1c6d67bc8b7ae11514a71abd6f8e6f64a4e17 Mon Sep 17 00:00:00 2001
From: Pauli Virtanen <pav@iki.fi>
Date: Thu, 20 Mar 2025 20:35:46 +0200
Subject: [PATCH] alsa: seq: double-check midi client version

Check midi client version after setting it, to see if it was really
successfully set.  Old kernels without UMP don't know about the midi
version fields, so snd_seq_set_client_midi_version() appears to fail
silently there.
---
 spa/plugins/alsa/alsa-seq.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/spa/plugins/alsa/alsa-seq.c b/spa/plugins/alsa/alsa-seq.c
index 23b74d0a2..3b740f47e 100644
--- a/spa/plugins/alsa/alsa-seq.c
+++ b/spa/plugins/alsa/alsa-seq.c
@@ -44,9 +44,27 @@ static int seq_open(struct seq_state *state, struct seq_conn *conn, bool with_qu
 
 #ifdef HAVE_ALSA_UMP
 	res = snd_seq_set_client_midi_version(conn->hndl, SND_SEQ_CLIENT_UMP_MIDI_2_0);
+	if (!res) {
+		snd_seq_client_info_t *info = NULL;
+
+		/* Double check client version */
+		res = snd_seq_client_info_malloc(&info);
+		if (!res)
+			res = snd_seq_get_client_info(conn->hndl, info);
+		if (!res) {
+			res = snd_seq_client_info_get_midi_version(info);
+			if (res == SND_SEQ_CLIENT_UMP_MIDI_2_0)
+				res = 0;
+			else
+				res = -EIO;
+		}
+		if (info)
+			snd_seq_client_info_free(info);
+	}
 #else
 	res = -EOPNOTSUPP;
 #endif
+
 	if (res < 0) {
 		spa_log_lev(state->log, (probe_ump ? SPA_LOG_LEVEL_INFO : SPA_LOG_LEVEL_ERROR),
 				"%p: ALSA failed to enable UMP MIDI: %s", state, snd_strerror(res));