$ cat patches/0002-ALSA-backend-for-Firefox-Fix-device-enumeration-and-.patch
From 69df295f5cf8d80f594110f9576a7bed153295b5 Mon Sep 17 00:00:00 2001
From: Devuan
Date: Thu, 11 Jun 2026 21:58:59 +0200
Subject: [PATCH 2/3] ALSA backend for Firefox: Fix device enumeration and max
 channel count

- Replace placeholder device enumeration with proper ALSA device
  discovery using snd_card_next() and snd_ctl_pcm_next_device() to
  report actual audio devices with their real capabilities instead of
  a single fictional default device.

- Cap max channel count at 64 to sanitize unrealistic values returned
  by snd_pcm_hw_params_get_channels_max() which can report placeholder
  values like 10000 from some drivers.
---
 src/cubeb_alsa.c | 160 +++++++++++++++++++++++++++++++++--------------
 1 file changed, 114 insertions(+), 46 deletions(-)

diff --git a/src/cubeb_alsa.c b/src/cubeb_alsa.c
index be9faa4..b76ec4f 100644
--- a/src/cubeb_alsa.c
+++ b/src/cubeb_alsa.c
@@ -1223,6 +1223,11 @@ alsa_get_max_channel_count(cubeb * ctx, uint32_t * max_channels)
     return CUBEB_ERROR;
   }
 
+  /* Cap at reasonable maximum to filter driver placeholder values */  
+  if (*max_channels > 64) {  
+    *max_channels = 64;  
+  }  
+
   alsa_stream_destroy(stm);
 
   return CUBEB_OK;
@@ -1412,61 +1417,124 @@ static int
 alsa_enumerate_devices(cubeb * context, cubeb_device_type type,
                        cubeb_device_collection * collection)
 {
-  cubeb_device_info * device = NULL;
+  cubeb_device_info * device;
+  snd_pcm_info_t * pcminfo;
+  snd_ctl_t * ctl;
+  snd_ctl_card_info_t * cardinfo;
+  int card = -1;
+  char card_name[32];
+  int err;
+  int dev;
+  snd_pcm_stream_t stream;
+
+  snd_pcm_info_alloca(&pcminfo);
+  snd_ctl_card_info_alloca(&cardinfo);
+
+  collection->count = 0;
+  collection->device = NULL;
+
+  if (snd_card_next(&card) < 0 || card < 0)
+    return CUBEB_OK;
 
-  if (!context)
-    return CUBEB_ERROR;
+  while (card >= 0) {
+    sprintf(card_name, "hw:%d", card);
+    err = snd_ctl_open(&ctl, card_name, 0);
+    if (err < 0) {
+      snd_card_next(&card);
+      continue;
+    }
 
-  uint32_t rate, max_channels;
-  int r;
+    err = snd_ctl_card_info(ctl, cardinfo);
+    if (err < 0) {
+      snd_ctl_close(ctl);
+      snd_card_next(&card);
+      continue;
+    }
 
-  r = alsa_get_preferred_sample_rate(context, &rate);
-  if (r != CUBEB_OK) {
-    return CUBEB_ERROR;
-  }
+    dev = -1;
+    while (1) {
+      if (snd_ctl_pcm_next_device(ctl, &dev) < 0)
+        break;
+      if (dev < 0)
+        break;
+
+      for (stream = 0; stream < 2; stream++) {
+        if ((type & CUBEB_DEVICE_TYPE_OUTPUT) && stream == SND_PCM_STREAM_CAPTURE)
+          continue;
+        if ((type & CUBEB_DEVICE_TYPE_INPUT) && stream == SND_PCM_STREAM_PLAYBACK)
+          continue;
+
+        snd_pcm_info_set_device(pcminfo, dev);
+        snd_pcm_info_set_subdevice(pcminfo, 0);
+        snd_pcm_info_set_stream(pcminfo, stream);
+        err = snd_ctl_pcm_info(ctl, pcminfo);
+        if (err < 0)
+          continue;
+
+        device = (cubeb_device_info *)calloc(1, sizeof(cubeb_device_info));
+        if (!device) {
+          snd_ctl_close(ctl);
+          return CUBEB_ERROR;
+        }
 
-  r = alsa_get_max_channel_count(context, &max_channels);
-  if (r != CUBEB_OK) {
-    return CUBEB_ERROR;
+        device->device_id = strdup(snd_pcm_info_get_name(pcminfo));
+        device->friendly_name = strdup(snd_pcm_info_get_name(pcminfo));
+        device->group_id = strdup(snd_ctl_card_info_get_id(cardinfo));
+        device->vendor_name = strdup(snd_ctl_card_info_get_name(cardinfo));
+
+        device->type = (stream == SND_PCM_STREAM_PLAYBACK) ? 
+                       CUBEB_DEVICE_TYPE_OUTPUT : CUBEB_DEVICE_TYPE_INPUT;
+        device->devid = (void *)(intptr_t)(card << 16 | dev);
+        device->state = CUBEB_DEVICE_STATE_ENABLED;
+        device->preferred = (dev == 0);
+        
+        device->max_channels = 8;  
+        
+        device->min_rate = 8000;   /* Conservative minimum */ 
+        device->max_rate = 192000; /* Conservative maximum */
+        device->default_format = (cubeb_device_fmt)CUBEB_SAMPLE_FLOAT32NE;
+        device->latency_lo = 0;
+        device->latency_hi = 0;
+
+        collection->count++;
+        collection->device = (cubeb_device_info *)realloc(collection->device,
+                                                         collection->count * sizeof(cubeb_device_info));
+        if (!collection->device) {
+          free((void *)device->device_id);  
+          free((void *)device->friendly_name);  
+          free((void *)device->group_id);  
+          free((void *)device->vendor_name);
+          free(device);
+          snd_ctl_close(ctl);
+          return CUBEB_ERROR;
+        }
+        collection->device[collection->count - 1] = *device;
+        free(device);
+      }
+    }
+    snd_ctl_close(ctl);
+    snd_card_next(&card);
   }
 
-  char const * a_name = "default";
-  device = (cubeb_device_info *)calloc(1, sizeof(cubeb_device_info));
-  assert(device);
-  if (!device)
-    return CUBEB_ERROR;
-
-  device->device_id = a_name;
-  device->devid = (cubeb_devid)device->device_id;
-  device->friendly_name = a_name;
-  device->group_id = a_name;
-  device->vendor_name = a_name;
-  device->type = type;
-  device->state = CUBEB_DEVICE_STATE_ENABLED;
-  device->preferred = CUBEB_DEVICE_PREF_ALL;
-  device->format = CUBEB_DEVICE_FMT_S16NE;
-  device->default_format = CUBEB_DEVICE_FMT_S16NE;
-  device->max_channels = max_channels;
-  device->min_rate = rate;
-  device->max_rate = rate;
-  device->default_rate = rate;
-  device->latency_lo = 0;
-  device->latency_hi = 0;
-
-  collection->device = device;
-  collection->count = 1;
-
   return CUBEB_OK;
 }
 
-static int
-alsa_device_collection_destroy(cubeb * context,
-                               cubeb_device_collection * collection)
-{
-  assert(collection->count == 1);
-  (void)context;
-  free(collection->device);
-  return CUBEB_OK;
+static int  
+alsa_device_collection_destroy(cubeb * context,  
+                               cubeb_device_collection * collection)  
+{  
+  size_t i;  
+  
+  (void)context;  
+  
+  for (i = 0; i < collection->count; ++i) {  
+    free((void *)collection->device[i].device_id);  
+    free((void *)collection->device[i].friendly_name);  
+    free((void *)collection->device[i].group_id);  
+    free((void *)collection->device[i].vendor_name);  
+  }  
+  free(collection->device);  
+  return CUBEB_OK;  
 }
 
 static struct cubeb_ops const alsa_ops = {
-- 
2.39.5

$ ls -1 /usr/share/alsa/alsa.conf.d
10-rate-lav.conf
10-samplerate.conf
10-speexrate.conf
50-arcam-av-ctl.conf
50-jack.conf
50-oss.conf
60-a52-encoder.conf
60-speex.conf
60-upmix.conf
60-vdownmix.conf
98-usb-stream.conf

$ ls -l -1 /etc/alsa/conf.d
total 0
lrwxrwxrwx 1 root root 44 Jul  1  2024 10-rate-lav.conf -> /usr/share/alsa/alsa.conf.d/10-rate-lav.conf
lrwxrwxrwx 1 root root 46 Jul  1  2024 10-samplerate.conf -> /usr/share/alsa/alsa.conf.d/10-samplerate.conf
lrwxrwxrwx 1 root root 45 Jul  1  2024 10-speexrate.conf -> /usr/share/alsa/alsa.conf.d/10-speexrate.conf
lrwxrwxrwx 1 root root 48 Jul  1  2024 50-arcam-av-ctl.conf -> /usr/share/alsa/alsa.conf.d/50-arcam-av-ctl.conf
lrwxrwxrwx 1 root root 40 Jul  1  2024 50-jack.conf -> /usr/share/alsa/alsa.conf.d/50-jack.conf
lrwxrwxrwx 1 root root 39 Jul  1  2024 50-oss.conf -> /usr/share/alsa/alsa.conf.d/50-oss.conf
lrwxrwxrwx 1 root root 47 Jul  1  2024 60-a52-encoder.conf -> /usr/share/alsa/alsa.conf.d/60-a52-encoder.conf
lrwxrwxrwx 1 root root 41 Jul  1  2024 60-speex.conf -> /usr/share/alsa/alsa.conf.d/60-speex.conf
lrwxrwxrwx 1 root root 41 Jul  1  2024 60-upmix.conf -> /usr/share/alsa/alsa.conf.d/60-upmix.conf
lrwxrwxrwx 1 root root 44 Jul  1  2024 60-vdownmix.conf -> /usr/share/alsa/alsa.conf.d/60-vdownmix.conf
lrwxrwxrwx 1 root root 46 Jul  1  2024 98-usb-stream.conf -> /usr/share/alsa/alsa.conf.d/98-usb-stream.conf

$ apt-file find 99-pulseaudio-default.conf.example
libasound2-plugins: /etc/alsa/conf.d/99-pulseaudio-default.conf.example

$ ls -1 /usr/share/alsa/alsa.conf.d
10-rate-lav.conf
10-samplerate.conf
10-speexrate.conf
50-arcam-av-ctl.conf
50-jack.conf
50-oss.conf
50-pulseaudio.conf
60-a52-encoder.conf
60-speex.conf
60-upmix.conf
60-vdownmix.conf
98-usb-stream.conf
$ 

$ ls -1 /etc/alsa/conf.d
10-rate-lav.conf
10-samplerate.conf
10-speexrate.conf
50-arcam-av-ctl.conf
50-jack.conf
50-oss.conf
50-pulseaudio.conf
60-a52-encoder.conf
60-speex.conf
60-upmix.conf
60-vdownmix.conf
98-usb-stream.conf
99-pulseaudio-default.conf.example
$ 

$ cat /etc/alsa/conf.d/99-pulseaudio-default.conf.example
# Default to PulseAudio

pcm.!default {
    type pulse
    hint {
        show on
        description "Default ALSA Output (currently PulseAudio Sound Server)"
    }
}

ctl.!default {
    type pulse
}
$ 

arecord -f cd -V mono | aplay