[pulseaudio-commits] [Git][pulseaudio/pulseaudio][master] combine-sink: Fix threading issue during underrun

[PulseAudio Marge Bot (@pulseaudio-merge-bot)]

PulseAudio Marge Bot pushed to branch master at PulseAudio / pulseaudio


Commits:
ee8bfb49 by Georg Chini at 2022-06-17T12:57:24+00:00
combine-sink: Fix threading issue during underrun

A recent commit added i->origin sink for the sink inputs of the combine sinks.
Therefore pa_sink_process_input_underruns() treated the combine sink like
filter sinks. pa_sink_process_input_underruns() calls itself with the
origin sink, which is only correct for filter sinks because they run in the
thread context of the origin sink. The combine sink however has its own
thread context, so pa_sink_process_input_underruns() was executed in the
wrong context.
This patch fixes the issue by skipping the section for module-combine-sink.

Part-of: <https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/merge_requests/722>

- - - - -


1 changed file:

- src/pulsecore/sink.c


Changes:

=====================================
src/pulsecore/sink.c
=====================================
@@ -1016,20 +1016,29 @@ size_t pa_sink_process_input_underruns(pa_sink *s, size_t left_to_play) {
         if (i->origin_sink) {
             size_t filter_result, left_to_play_origin;
 
-            /* The recursive call works in the origin sink domain ... */
-            left_to_play_origin = pa_convert_size(left_to_play, &i->sink->sample_spec, &i->origin_sink->sample_spec);
-
-            /* .. and returns the time to sleep before waking up. We need the
-             * underrun duration for comparisons, so we undo the subtraction on
-             * the return value... */
-            filter_result = left_to_play_origin - pa_sink_process_input_underruns(i->origin_sink, left_to_play_origin);
-
-            /* ... and convert it back to the master sink domain */
-            filter_result = pa_convert_size(filter_result, &i->origin_sink->sample_spec, &i->sink->sample_spec);
-
-            /* Remember the longest underrun so far */
-            if (filter_result > result)
-                result = filter_result;
+            /* The combine sink sets i->origin sink but has a different threading model
+             * than the filter sinks. Therefore the recursion below may not be executed
+             * because pa_sink_process_input_underruns() was not called in the thread
+             * context of the origin sink.
+             * FIXME: It is unclear if some other kind of recursion would be necessary
+             * for the combine sink. */
+            if (!i->module || !pa_safe_streq(i->module->name, "module-combine-sink")) {
+
+                /* The recursive call works in the origin sink domain ... */
+                left_to_play_origin = pa_convert_size(left_to_play, &i->sink->sample_spec, &i->origin_sink->sample_spec);
+
+                /* .. and returns the time to sleep before waking up. We need the
+                 * underrun duration for comparisons, so we undo the subtraction on
+                 * the return value... */
+                filter_result = left_to_play_origin - pa_sink_process_input_underruns(i->origin_sink, left_to_play_origin);
+
+                /* ... and convert it back to the master sink domain */
+                filter_result = pa_convert_size(filter_result, &i->origin_sink->sample_spec, &i->sink->sample_spec);
+
+                /* Remember the longest underrun so far */
+                if (filter_result > result)
+                    result = filter_result;
+            }
         }
 
         if (uf == 0) {



View it on GitLab: https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/commit/ee8bfb49adddd271d8a8cafa796c6f9fa84de48a

-- 
View it on GitLab: https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/commit/ee8bfb49adddd271d8a8cafa796c6f9fa84de48a
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