sndworker: add AudioVolume/AudioMute messages

These messages allow the guest to send the audio device volume to the
client. It uses an arbitrary scale of 16bits, which works good enough
for now.

Save VolumeState in {Playback,Record}State, so that we can send the
current volume on channel connection.

Note about future improvements:
- add exact dB support
- add client to guest volume change

Updated since v2:
- bumped record and playback interface minor version to allow
  conditional compilation
Updated since v1:
- sync record volume on connection too

1 files changed, 8 insertions, 2 deletions

diff --git a/server/spice.h b/server/spice.h
index 425d5869..f64ff414 100644
--- a/server/spice.h
+++ b/server/spice.h
@@ -268,7 +268,7 @@ struct SpiceTabletInstance {
 
 #define SPICE_INTERFACE_PLAYBACK "playback"
 #define SPICE_INTERFACE_PLAYBACK_MAJOR 1
-#define SPICE_INTERFACE_PLAYBACK_MINOR 1
+#define SPICE_INTERFACE_PLAYBACK_MINOR 2
 typedef struct SpicePlaybackInterface SpicePlaybackInterface;
 typedef struct SpicePlaybackInstance SpicePlaybackInstance;
 typedef struct SpicePlaybackState SpicePlaybackState;
@@ -296,10 +296,13 @@ void spice_server_playback_get_buffer(SpicePlaybackInstance *sin,
                                       uint32_t **samples, uint32_t *nsamples);
 void spice_server_playback_put_samples(SpicePlaybackInstance *sin,
                                        uint32_t *samples);
+void spice_server_playback_set_volume(SpicePlaybackInstance *sin,
+                                      uint8_t nchannels, uint16_t *volume);
+void spice_server_playback_set_mute(SpicePlaybackInstance *sin, uint8_t mute);
 
 #define SPICE_INTERFACE_RECORD "record"
 #define SPICE_INTERFACE_RECORD_MAJOR 2
-#define SPICE_INTERFACE_RECORD_MINOR 1
+#define SPICE_INTERFACE_RECORD_MINOR 2
 typedef struct SpiceRecordInterface SpiceRecordInterface;
 typedef struct SpiceRecordInstance SpiceRecordInstance;
 typedef struct SpiceRecordState SpiceRecordState;
@@ -321,6 +324,9 @@ void spice_server_record_start(SpiceRecordInstance *sin);
 void spice_server_record_stop(SpiceRecordInstance *sin);
 uint32_t spice_server_record_get_samples(SpiceRecordInstance *sin,
                                          uint32_t *samples, uint32_t bufsize);
+void spice_server_record_set_volume(SpiceRecordInstance *sin,
+                                    uint8_t nchannels, uint16_t *volume);
+void spice_server_record_set_mute(SpiceRecordInstance *sin, uint8_t mute);
 
 /* char device interfaces */