Re: [PATCH 5/7] audio: do not use first -audiodev as default audio device

[BALATON Zoltan]

On Thu, 5 Oct 2023, BALATON Zoltan wrote:
On Thu, 5 Oct 2023, Paolo Bonzini wrote:
It is now possible to specify the options for the default audio device
using -audio, so there is no need anymore to use a fake -audiodev option.
Remove the fall back to QTAILQ_FIRST(&audio_states), instead remember the
AudioState that was created from default_audiodevs and use that one.

Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
---
audio/audio.c                   | 25 +++++++------------------
docs/about/deprecated.rst       |  6 ------
docs/about/removed-features.rst |  8 ++++++++
3 files changed, 15 insertions(+), 24 deletions(-)

diff --git a/audio/audio.c b/audio/audio.c
index 186cc4d336e..de37ad7c074 100644
--- a/audio/audio.c
+++ b/audio/audio.c
@@ -104,6 +104,7 @@ static audio_driver *audio_driver_lookup(const char 
*name)

static QTAILQ_HEAD(AudioStateHead, AudioState) audio_states =
    QTAILQ_HEAD_INITIALIZER(audio_states);
+static AudioState *default_audio_state;

const struct mixeng_volume nominal_volume = {
    .mute = 0,
@@ -1660,6 +1661,7 @@ static void free_audio_state(AudioState *s)

void audio_cleanup(void)
{
+    default_audio_state = NULL;
    while (!QTAILQ_EMPTY(&audio_states)) {
        AudioState *s = QTAILQ_FIRST(&audio_states);
        QTAILQ_REMOVE(&audio_states, s, list);
@@ -1760,6 +1762,7 @@ static AudioState *audio_init(Audiodev *dev, Error 
**errp)
            goto out;
        }
    } else {
+        assert(!default_audio_state);
        for (;;) {
            AudiodevListEntry *e = QSIMPLEQ_FIRST(&default_audiodevs);
            if (!e) {
@@ -1801,24 +1804,9 @@ out:
bool AUD_register_card (const char *name, QEMUSoundCard *card, Error 
**errp)
{
    if (!card->state) {
-        if (!QTAILQ_EMPTY(&audio_states)) {
-            /*
-             * FIXME: once it is possible to create an arbitrary
-             * default device via -audio DRIVER,OPT=VALUE (no "model"),
-             * replace this special case with the default AudioState*,
-             * storing it in a separate global.  For now, keep the
-             * warning to encourage moving off magic use of the first
-             * -audiodev.
-             */
-            if (QSIMPLEQ_EMPTY(&default_audiodevs)) {
-                dolog("Device %s: audiodev default parameter is 
deprecated, please "
-                      "specify audiodev=%s\n", name,
-                      QTAILQ_FIRST(&audio_states)->dev->id);
-            }
-            card->state = QTAILQ_FIRST(&audio_states);
-        } else {
-            card->state = audio_init(NULL, errp);
-            if (!card->state) {
+        if (!default_audio_state) {
+            default_audio_state = audio_init(NULL, errp);
+            if (!default_audio_state) {
                if (!QSIMPLEQ_EMPTY(&audiodevs)) {
                    error_append_hint(errp, "Perhaps you wanted to set 
audiodev=%s?\n",
                                      QSIMPLEQ_FIRST(&audiodevs)->dev->id);
@@ -1826,6 +1814,7 @@ bool AUD_register_card (const char *name, 
QEMUSoundCard *card, Error **errp)
                return false;
            }
        }
+        card->state = default_audio_state;
    }

    card->name = g_strdup (name);
diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst
index 2f51cf770ae..d59bcf36230 100644
--- a/docs/about/deprecated.rst
+++ b/docs/about/deprecated.rst
@@ -37,12 +37,6 @@ coverage.
System emulator command line arguments
--------------------------------------

-Creating sound card devices without ``audiodev=`` property (since 4.2)
-''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
-
-When not using the deprecated legacy audio config, each sound card
-should specify an ``audiodev=`` property.
-
Short-form boolean options (since 6.0)
''''''''''''''''''''''''''''''''''''''

diff --git a/docs/about/removed-features.rst 
b/docs/about/removed-features.rst
index 58c94392c65..27639370f96 100644
--- a/docs/about/removed-features.rst
+++ b/docs/about/removed-features.rst
@@ -442,10 +442,18 @@ line using a ``secret`` object instance.
The ``-audiodev`` and ``-audio`` command line options are now the only
way to specify audio backend settings.

+Using ``-audiodev`` to define the default audio backend (removed in 8.2)
+''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
+
QEMU does not create default audio backends anymore if any of the
``-audiodev``, ``-audio`` or ``-nodefaults`` options are used on the
command line.

Maybe this needs further updating because -audio can now define the default 
and is what should be used instead of -audiodev but this is not clear from 
this documentation.

And while at it, maybe also mention machine audiodev property here as a 
way to set audiodev of embedded devices.

Regards,
BALATON Zoltan

+If an audio backend is created with ``-audiodev``, each sound card
+that wants to use it should specify an ``audiodev=``
+property.  Previously, the first audiodev command line option would be
+used as a fallback.
+
Creating vnc without ``audiodev=`` property (removed in 8.2)
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''