audio: disable default backends if -audio/-audiodev is used

Match what is done for other options, for example -monitor, and also
the behavior of QEMU 8.1 (see the "legacy_config" variable).  Require
the user to specify a backend if one is specified on the command line.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

audio/audio.c

@@ -1688,14 +1688,10 @@ static const VMStateDescription vmstate_audio = {
 
 static void audio_validate_opts(Audiodev *dev, Error **errp);
 
-static void audio_create_default_audiodevs(void)
+void audio_create_default_audiodevs(void)
 {
     const char *drvname = getenv("QEMU_AUDIO_DRV");
 
-    if (!defaults_enabled()) {
-        return;
-    }
-
     /* QEMU_AUDIO_DRV=none is used by libqtest.  */
     if (drvname && !g_str_equal(drvname, "none")) {
         error_report("Please use -audiodev instead of QEMU_AUDIO_*");
@@ -1827,9 +1823,6 @@ bool AUD_register_card (const char *name, QEMUSoundCard *card, Error **errp)
             }
             card->state = QTAILQ_FIRST(&audio_states);
         } else {
-            if (QSIMPLEQ_EMPTY(&default_audiodevs)) {
-                audio_create_default_audiodevs();
-            }
             card->state = audio_init(NULL, errp);
             if (!card->state) {
                 if (!QSIMPLEQ_EMPTY(&audiodevs)) {

audio/audio.h

@@ -170,6 +170,7 @@ void audio_sample_from_uint64(void *samples, int pos,
 
 void audio_define(Audiodev *audio);
 void audio_parse_option(const char *opt);
+void audio_create_default_audiodevs(void);
 void audio_init_audiodevs(void);
 void audio_help(void);
 

docs/about/removed-features.rst

@@ -442,6 +442,9 @@ line using a ``secret`` object instance.
 The ``-audiodev`` and ``-audio`` command line options are now the only
 way to specify audio backend settings.
 
+Note that the default audio backend must be configured on the command
+line if the ``-nodefaults`` options is used.
+
 Creating vnc without ``audiodev=`` property (removed in 8.2)
 ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
 

system/vl.c

@@ -184,6 +184,7 @@ static const char *qtest_log;
 static bool opt_one_insn_per_tb;
 
 static int has_defaults = 1;
+static int default_audio = 1;
 static int default_serial = 1;
 static int default_parallel = 1;
 static int default_monitor = 1;
@@ -1327,6 +1328,7 @@ static void qemu_disable_default_devices(void)
         default_sdcard = 0;
     }
     if (!has_defaults) {
+        default_audio = 0;
         default_monitor = 0;
         default_net = 0;
         default_vga = 0;
@@ -1963,6 +1965,9 @@ static void qemu_create_early_backends(void)
      */
     configure_blockdev(&bdo_queue, machine_class, snapshot);
     audio_init_audiodevs();
+    if (default_audio) {
+        audio_create_default_audiodevs();
+    }
 }
 
 
@@ -2925,6 +2930,7 @@ void qemu_init(int argc, char **argv)
                 break;
 #endif
             case QEMU_OPTION_audiodev:
+                default_audio = 0;
                 audio_parse_option(optarg);
                 break;
             case QEMU_OPTION_audio: {
@@ -2933,6 +2939,7 @@ void qemu_init(int argc, char **argv)
                 Audiodev *dev = NULL;
                 Visitor *v;
                 QDict *dict = keyval_parse(optarg, "driver", &help, &error_fatal);
+                default_audio = 0;
                 if (help || (qdict_haskey(dict, "driver") &&
                              is_help_option(qdict_get_str(dict, "driver")))) {
                     audio_help();