paaudio: wait until the playback stream is ready

Don't call pa_stream_writable_size() in qpa_get_buffer_out()
before the playback stream is ready. This prevents a lot of the
following pulseaudio error messages.

pulseaudio: pa_stream_writable_size failed
pulseaudio: Reason: Bad state

To reproduce start qemu with
-parallel none -device gus,audiodev=audio0 -audiodev pa,id=audio0

Signed-off-by: Volker Rümelin <vr_qemu@t-online.de>
Message-id: 9315afe5-5958-c0b4-ea1e-14769511a9d5@t-online.de
Message-Id: <20210110100239.27588-15-vr_qemu@t-online.de>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/audio/paaudio.c b/audio/paaudio.c
index 1a7252b..4a1ffda 100644
--- a/audio/paaudio.c
+++ b/audio/paaudio.c
@@ -214,6 +214,12 @@ static void *qpa_get_buffer_out(HWVoiceOut *hw, size_t *size)
 
     CHECK_DEAD_GOTO(c, p->stream, unlock_and_fail,
                     "pa_threaded_mainloop_lock failed\n");
+    if (pa_stream_get_state(p->stream) != PA_STREAM_READY) {
+        /* wait for stream to become ready */
+        l = 0;
+        ret = NULL;
+        goto unlock;
+    }
 
     l = pa_stream_writable_size(p->stream);
     CHECK_SUCCESS_GOTO(c, l != (size_t) -1, unlock_and_fail,
@@ -224,6 +230,7 @@ static void *qpa_get_buffer_out(HWVoiceOut *hw, size_t *size)
     CHECK_SUCCESS_GOTO(c, r >= 0, unlock_and_fail,
                        "pa_stream_begin_write failed\n");
 
+unlock:
     pa_threaded_mainloop_unlock(c->mainloop);
     if (*size > l) {
         *size = l;