audio: refactor some aspects of filter chain setup

There's no real reason why audio_init_filter() should exist. Just use
af_init or af_reinit directly. (We lose a useless message; the same
information is printed in a quite close place with more details.)

Requires less code, and the way the filter chain is marked as having
failed to initialize allows just switching off audio instead of
crashing if trying to insert a volume filter in mixer.c fails, and
recreating the old filter chain fails too.

1 files changed, 2 insertions, 0 deletions

diff --git a/audio/filter/af.h b/audio/filter/af.h
index bec0e823fe..579ac271ef 100644
--- a/audio/filter/af.h
+++ b/audio/filter/af.h
@@ -80,6 +80,8 @@ struct af_instance {
 
 // Current audio stream
 struct af_stream {
+    int initialized; // 0: no, 1: yes, -1: attempted to, but failed
+
     // The first and last filter in the list
     struct af_instance *first;
     struct af_instance *last;