core: make fixed latency dynamically changeable

This of course makes the name 'fixed' a bit of a misnomer. However the
definitions are now like this:

fixed latency: the latency may change during runtime, but is solely
controlled by the backend, the client has no influence.

dynamic latency: the latency may change during runtime, influenced by
the requests of the clients.

i.e. fixed vs. dynamic is from the perspective of the client.

1 files changed, 15 insertions, 3 deletions

diff --git a/src/pulsecore/sink.h b/src/pulsecore/sink.h
index 33145df3..55bca7f4 100644
--- a/src/pulsecore/sink.h
+++ b/src/pulsecore/sink.h
@@ -105,8 +105,6 @@ struct pa_sink {
 
     pa_memchunk silence;
 
-    pa_usec_t fixed_latency; /* for sinks with PA_SINK_DYNAMIC_LATENCY this is 0 */
-
     pa_hashmap *ports;
     pa_device_port *active_port;
 
@@ -160,6 +158,9 @@ struct pa_sink {
         pa_cvolume soft_volume;
         pa_bool_t soft_muted:1;
 
+        /* The requested latency is used for dynamic latency
+         * sinks. For fixed latency sinks it is always identical to
+         * the fixed_latency. See below. */
         pa_bool_t requested_latency_valid:1;
         pa_usec_t requested_latency;
 
@@ -175,8 +176,15 @@ struct pa_sink {
         size_t rewind_nbytes;
         pa_bool_t rewind_requested;
 
+        /* Both dynamic and fixed latencies will be clamped to this
+         * range. */
         pa_usec_t min_latency; /* we won't go below this latency */
         pa_usec_t max_latency; /* An upper limit for the latencies */
+
+        /* 'Fixed' simply means that the latency is exclusively
+         * decided on by the sink, and the clients have no influence
+         * in changing it */
+        pa_usec_t fixed_latency; /* for sinks with PA_SINK_DYNAMIC_LATENCY this is 0 */
     } thread_info;
 
     void *userdata;
@@ -202,6 +210,8 @@ typedef enum pa_sink_message {
     PA_SINK_MESSAGE_DETACH,
     PA_SINK_MESSAGE_SET_LATENCY_RANGE,
     PA_SINK_MESSAGE_GET_LATENCY_RANGE,
+    PA_SINK_MESSAGE_SET_FIXED_LATENCY,
+    PA_SINK_MESSAGE_GET_FIXED_LATENCY,
     PA_SINK_MESSAGE_GET_MAX_REWIND,
     PA_SINK_MESSAGE_GET_MAX_REQUEST,
     PA_SINK_MESSAGE_SET_MAX_REWIND,
@@ -282,6 +292,7 @@ pa_bool_t pa_device_init_intended_roles(pa_proplist *p);
 pa_usec_t pa_sink_get_latency(pa_sink *s);
 pa_usec_t pa_sink_get_requested_latency(pa_sink *s);
 void pa_sink_get_latency_range(pa_sink *s, pa_usec_t *min_latency, pa_usec_t *max_latency);
+pa_usec_t pa_sink_get_fixed_latency(pa_sink *s);
 
 size_t pa_sink_get_max_rewind(pa_sink *s);
 size_t pa_sink_get_max_request(pa_sink *s);
@@ -333,12 +344,13 @@ void pa_sink_set_max_rewind_within_thread(pa_sink *s, size_t max_rewind);
 void pa_sink_set_max_request_within_thread(pa_sink *s, size_t max_request);
 
 void pa_sink_set_latency_range_within_thread(pa_sink *s, pa_usec_t min_latency, pa_usec_t max_latency);
+void pa_sink_set_fixed_latency_within_thread(pa_sink *s, pa_usec_t latency);
 
 /*** To be called exclusively by sink input drivers, from IO context */
 
 void pa_sink_request_rewind(pa_sink*s, size_t nbytes);
 
-void pa_sink_invalidate_requested_latency(pa_sink *s);
+void pa_sink_invalidate_requested_latency(pa_sink *s, pa_bool_t dynamic);
 
 pa_usec_t pa_sink_get_latency_within_thread(pa_sink *s);