diff --git a/spa/plugins/alsa/acp/alsa-mixer.c b/spa/plugins/alsa/acp/alsa-mixer.c
index b18d7c6c9..7d86720d8 100644
--- a/spa/plugins/alsa/acp/alsa-mixer.c
+++ b/spa/plugins/alsa/acp/alsa-mixer.c
@@ -1544,13 +1544,23 @@ int pa_alsa_path_select(pa_alsa_path *p, pa_alsa_setting *s, snd_mixer_t *m, boo
     if (s)
         setting_select(s, m);
 
-    /* Finally restore hw mute to the device mute status. */
-    if (p->mute_during_activation) {
-        PA_LLIST_FOREACH(e, p->elements) {
-            if (e->switch_use == PA_ALSA_SWITCH_MUTE) {
-                if (element_set_switch(e, m, !device_is_muted) < 0)
-                    return -1;
-            }
+    /* Set hw mute switches to match device mute status.
+     *
+     * When mute_during_activation is enabled, switches are temporarily muted
+     * during path setup to avoid pops/clicks, and this restores them.
+     *
+     * When mute_during_activation is disabled (default), switches may still be
+     * in their kernel default state (often muted for digital outputs like IEC958).
+     * We must explicitly unmute them if the device isn't muted.
+     *
+     * This ensures HDMI/DisplayPort audio (IEC958) works correctly, as these
+     * digital output switches default to muted in ALSA drivers but are not
+     * automatically enabled when the path is selected.
+     */
+    PA_LLIST_FOREACH(e, p->elements) {
+        if (e->switch_use == PA_ALSA_SWITCH_MUTE) {
+            if (element_set_switch(e, m, !device_is_muted) < 0)
+                return -1;
         }
     }
 
diff --git a/spa/plugins/alsa/acp/meson.build b/spa/plugins/alsa/acp/meson.build
index 0ec97e2b4..f5adfa193 100644
--- a/spa/plugins/alsa/acp/meson.build
+++ b/spa/plugins/alsa/acp/meson.build
@@ -20,3 +20,12 @@ acp_lib = static_library(
   dependencies : [ spa_dep, alsa_dep, mathlib, ]
   )
 acp_dep = declare_dependency(link_with: acp_lib)
+
+executable('test-alsa-path-select',
+  [ 'test-alsa-path-select.c' ],
+  c_args : acp_c_args,
+  include_directories : [configinc, includes_inc ],
+  dependencies : [ spa_dep, alsa_dep, mathlib, ],
+  link_with : [ acp_lib ],
+  install : false,
+)
diff --git a/spa/plugins/alsa/acp/test-alsa-path-select.c b/spa/plugins/alsa/acp/test-alsa-path-select.c
new file mode 100644
index 000000000..f30662d50
--- /dev/null
+++ b/spa/plugins/alsa/acp/test-alsa-path-select.c
@@ -0,0 +1,348 @@
+/* ALSA path select test tool */
+/* SPDX-FileCopyrightText: Copyright © 2025 Daniel Nouri */
+/* SPDX-License-Identifier: MIT */
+
+/*
+ * Tests pa_alsa_path_select() to verify mute switches are correctly set
+ * based on device mute status, regardless of mute_during_activation setting.
+ *
+ * Regression test for HDMI/DisplayPort audio bug where IEC958 switches
+ * remain in kernel default state (OFF) because pa_alsa_path_select() only
+ * set switches when mute_during_activation=true, but no paths enable this.
+ *
+ * Test verification:
+ *   Before fix: IEC958 switch stays OFF after path select → test FAILS
+ *   After fix:  IEC958 switch set correctly based on device state → test PASSES
+ *
+ * Usage:
+ *   test-alsa-path-select -c <card> [-p <path>] [-m] [-v]
+ *
+ * Examples:
+ *   test-alsa-path-select -c 1                  # IEC958 unmuted (expect ON)
+ *   test-alsa-path-select -c 1 -m               # IEC958 muted (expect OFF)
+ *   test-alsa-path-select -c 0 -p analog-output # Regression test
+ *
+ * Exit codes:
+ *   0 = Test passed
+ *   1 = Test failed
+ *   2 = Setup error
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+#include <errno.h>
+#include <getopt.h>
+#include <alsa/asoundlib.h>
+
+#include "alsa-mixer.h"
+#include "alsa-util.h"
+
+#define DEFAULT_PATHS_DIR "/usr/share/alsa-card-profile/mixer/paths"
+
+struct test_config {
+	int card;
+	const char *path_name;
+	const char *paths_dir;
+	bool device_muted;
+	bool verbose;
+};
+
+static void show_help(const char *name)
+{
+	printf("Usage: %s [options]\n", name);
+	printf("\n");
+	printf("Test tool for pa_alsa_path_select() - verifies IEC958 unmute fix\n");
+	printf("\n");
+	printf("Options:\n");
+	printf("  -c, --card <N>         ALSA card number (required)\n");
+	printf("  -p, --path <name>      Mixer path name (default: iec958-stereo-output)\n");
+	printf("  -d, --paths-dir <dir>  Path to mixer path configs (default: %s)\n", DEFAULT_PATHS_DIR);
+	printf("  -m, --muted            Test with device muted (default: unmuted)\n");
+	printf("  -v, --verbose          Verbose output\n");
+	printf("  -h, --help             Show this help\n");
+	printf("\n");
+	printf("Examples:\n");
+	printf("  # Test IEC958 unmute on card 1\n");
+	printf("  %s -c 1\n", name);
+	printf("\n");
+	printf("  # Test analog output\n");
+	printf("  %s -c 0 -p analog-output\n", name);
+	printf("\n");
+	printf("  # Test with device muted\n");
+	printf("  %s -c 1 -m\n", name);
+	printf("\n");
+	printf("Exit codes:\n");
+	printf("  0 - Test passed (switches set correctly)\n");
+	printf("  1 - Test failed (switches not set as expected)\n");
+	printf("  2 - Setup error (path not found, hardware error, etc.)\n");
+}
+
+static int parse_args(int argc, char *argv[], struct test_config *config)
+{
+	static const struct option long_options[] = {
+		{ "card",      required_argument, NULL, 'c' },
+		{ "path",      required_argument, NULL, 'p' },
+		{ "paths-dir", required_argument, NULL, 'd' },
+		{ "muted",     no_argument,       NULL, 'm' },
+		{ "verbose",   no_argument,       NULL, 'v' },
+		{ "help",      no_argument,       NULL, 'h' },
+		{ NULL, 0, NULL, 0 }
+	};
+
+	int c;
+	config->card = -1;
+	config->path_name = "iec958-stereo-output.conf";
+	config->paths_dir = DEFAULT_PATHS_DIR;
+	config->device_muted = false;
+	config->verbose = false;
+
+	while ((c = getopt_long(argc, argv, "c:p:d:mvh", long_options, NULL)) != -1) {
+		switch (c) {
+		case 'c':
+			config->card = atoi(optarg);
+			break;
+		case 'p':
+			config->path_name = optarg;
+			break;
+		case 'd':
+			config->paths_dir = optarg;
+			break;
+		case 'm':
+			config->device_muted = true;
+			break;
+		case 'v':
+			config->verbose = true;
+			break;
+		case 'h':
+			show_help(argv[0]);
+			return -1;
+		default:
+			show_help(argv[0]);
+			return -2;
+		}
+	}
+
+	if (config->card < 0) {
+		fprintf(stderr, "Error: Card number is required (-c <N>)\n\n");
+		show_help(argv[0]);
+		return -2;
+	}
+
+	return 0;
+}
+
+static int get_switch_state(snd_mixer_t *mixer, const char *name, int index, bool *state)
+{
+	snd_mixer_elem_t *elem;
+	snd_mixer_selem_id_t *sid;
+	int val;
+
+	snd_mixer_selem_id_alloca(&sid);
+	snd_mixer_selem_id_set_name(sid, name);
+	snd_mixer_selem_id_set_index(sid, index);
+
+	elem = snd_mixer_find_selem(mixer, sid);
+	if (!elem) {
+		fprintf(stderr, "Warning: Element '%s',%d not found\n", name, index);
+		return -ENOENT;
+	}
+
+	if (!snd_mixer_selem_has_playback_switch(elem)) {
+		fprintf(stderr, "Warning: Element '%s',%d has no playback switch\n", name, index);
+		return -EINVAL;
+	}
+
+	if (snd_mixer_selem_get_playback_switch(elem, SND_MIXER_SCHN_MONO, &val) < 0) {
+		if (snd_mixer_selem_get_playback_switch(elem, SND_MIXER_SCHN_FRONT_LEFT, &val) < 0) {
+			fprintf(stderr, "Error: Cannot read switch state for '%s',%d\n", name, index);
+			return -EIO;
+		}
+	}
+
+	*state = val ? true : false;
+	return 0;
+}
+
+int main(int argc, char *argv[])
+{
+	struct test_config config;
+	pa_alsa_path *path = NULL;
+	snd_mixer_t *mixer = NULL;
+	char card_name[64];
+	int ret = 2;  // Setup error by default
+	int err;
+
+	/* Parse arguments */
+	err = parse_args(argc, argv, &config);
+	if (err < 0) {
+		return err == -1 ? 0 : 2;  // -1 is help, -2 is error
+	}
+
+	printf("Testing pa_alsa_path_select() with:\n");
+	printf("  Card: %d\n", config.card);
+	printf("  Path: %s\n", config.path_name);
+	printf("  Paths dir: %s\n", config.paths_dir);
+	printf("  Device muted: %s\n", config.device_muted ? "yes" : "no");
+	printf("\n");
+
+	/* Load mixer path */
+	path = pa_alsa_path_new(config.paths_dir, config.path_name, PA_ALSA_DIRECTION_OUTPUT);
+	if (!path) {
+		fprintf(stderr, "Error: Failed to load path '%s' from %s\n",
+			config.path_name, config.paths_dir);
+		fprintf(stderr, "Make sure the path file exists: %s/%s.conf\n",
+			config.paths_dir, config.path_name);
+		goto cleanup;
+	}
+
+	/* Count elements BEFORE probing */
+	int element_count_before = 0;
+	pa_alsa_element *e_temp;
+	PA_LLIST_FOREACH(e_temp, path->elements) {
+		element_count_before++;
+	}
+	printf("Elements in path BEFORE probing: %d\n", element_count_before);
+
+	if (config.verbose && element_count_before > 0) {
+		printf("Loaded path: %s\n", path->name ? path->name : config.path_name);
+		printf("  mute_during_activation: %s\n", path->mute_during_activation ? "yes" : "no");
+		printf("  Elements:\n");
+
+		PA_LLIST_FOREACH(e_temp, path->elements) {
+			const char *switch_use;
+			switch (e_temp->switch_use) {
+			case PA_ALSA_SWITCH_MUTE: switch_use = "mute"; break;
+			case PA_ALSA_SWITCH_ON: switch_use = "on"; break;
+			case PA_ALSA_SWITCH_OFF: switch_use = "off"; break;
+			default: switch_use = "ignore"; break;
+			}
+			printf("    - %s (index %d): switch=%s\n",
+				e_temp->alsa_id.name, e_temp->alsa_id.index, switch_use);
+		}
+		printf("\n");
+	}
+
+	/* Open ALSA mixer */
+	snprintf(card_name, sizeof(card_name), "hw:%d", config.card);
+
+	if (snd_mixer_open(&mixer, 0) < 0) {
+		fprintf(stderr, "Error: Failed to open mixer\n");
+		goto cleanup;
+	}
+
+	if (snd_mixer_attach(mixer, card_name) < 0) {
+		fprintf(stderr, "Error: Failed to attach mixer to %s\n", card_name);
+		fprintf(stderr, "Make sure card %d exists (check with: aplay -l)\n", config.card);
+		goto cleanup;
+	}
+
+	if (snd_mixer_selem_register(mixer, NULL, NULL) < 0) {
+		fprintf(stderr, "Error: Failed to register mixer\n");
+		goto cleanup;
+	}
+
+	if (snd_mixer_load(mixer) < 0) {
+		fprintf(stderr, "Error: Failed to load mixer elements\n");
+		goto cleanup;
+	}
+
+	/* Probe the path to ensure elements are available */
+	printf("Probing path...\n");
+	if (pa_alsa_path_probe(path, NULL, mixer, false) < 0) {
+		fprintf(stderr, "Error: Path probe failed - required elements not found on card\n");
+		goto cleanup;
+	}
+	printf("Path probe: OK\n\n");
+
+	/* Record switch states before activation */
+	printf("Switch states BEFORE pa_alsa_path_select():\n");
+	pa_alsa_element *e;
+	int mute_switch_count = 0;
+	PA_LLIST_FOREACH(e, path->elements) {
+		if (e->switch_use == PA_ALSA_SWITCH_MUTE) {
+			bool state;
+			mute_switch_count++;
+			if (get_switch_state(mixer, e->alsa_id.name, e->alsa_id.index, &state) == 0) {
+				printf("  %s,%d = %s\n", e->alsa_id.name, e->alsa_id.index,
+					state ? "ON" : "OFF");
+			}
+		}
+	}
+
+	if (mute_switch_count == 0) {
+		fprintf(stderr, "Warning: No mute switches found in path\n");
+		printf("This test requires a path with switch=mute elements\n");
+		ret = 2;
+		goto cleanup;
+	}
+
+	/* Call pa_alsa_path_select() - THE FUNCTION UNDER TEST */
+	printf("\nCalling pa_alsa_path_select(path, NULL, mixer, device_is_muted=%s)...\n",
+		config.device_muted ? "true" : "false");
+
+	err = pa_alsa_path_select(path, NULL, mixer, config.device_muted);
+	if (err < 0) {
+		fprintf(stderr, "Error: pa_alsa_path_select() failed with error %d\n", err);
+		ret = 2;
+		goto cleanup;
+	}
+	printf("pa_alsa_path_select(): OK\n\n");
+
+	/* Verify switch states after activation */
+	printf("Switch states AFTER pa_alsa_path_select():\n");
+	bool all_correct = true;
+	bool expected_state = !config.device_muted;  // unmuted device = switches ON
+
+	PA_LLIST_FOREACH(e, path->elements) {
+		if (e->switch_use == PA_ALSA_SWITCH_MUTE) {
+			bool actual_state;
+			if (get_switch_state(mixer, e->alsa_id.name, e->alsa_id.index, &actual_state) == 0) {
+				printf("  %s,%d = %s", e->alsa_id.name, e->alsa_id.index,
+					actual_state ? "ON" : "OFF");
+
+				if (actual_state == expected_state) {
+					printf(" ✓\n");
+				} else {
+					printf(" ✗ (expected %s)\n", expected_state ? "ON" : "OFF");
+					all_correct = false;
+				}
+			}
+		}
+	}
+
+	/* Determine test result */
+	printf("\n");
+	printf("========================================\n");
+	if (all_correct) {
+		printf("TEST PASSED\n");
+		printf("All mute switches correctly set to %s\n", expected_state ? "ON" : "OFF");
+		if (!path->mute_during_activation) {
+			printf("\nThis proves the fix works:\n");
+			printf("- Path has mute_during_activation=false (default)\n");
+			printf("- Switches were still set correctly\n");
+			printf("- Bug would have left them in kernel default state\n");
+		}
+		ret = 0;
+	} else {
+		printf("TEST FAILED\n");
+		printf("One or more switches NOT set correctly\n");
+		printf("Expected: %s, but some switches were %s\n",
+			expected_state ? "ON (unmuted)" : "OFF (muted)",
+			expected_state ? "OFF" : "ON");
+		printf("\nThis indicates the bug is still present:\n");
+		printf("- Switches not set when mute_during_activation=false\n");
+		printf("- IEC958 fix may not be applied\n");
+		ret = 1;
+	}
+	printf("========================================\n");
+
+cleanup:
+	if (mixer)
+		snd_mixer_close(mixer);
+	if (path)
+		pa_alsa_path_free(path);
+
+	return ret;
+}