From fa2b59df4b4dd0b480b3ee8d71d810e207cd806b Mon Sep 17 00:00:00 2001
From: Max Kellermann <max@musicpd.org>
Date: Mon, 15 May 2017 22:25:39 +0200
Subject: [PATCH] Main: cap buffer_before_play at 80% to prevent deadlock

Closes #34
---
 NEWS         |  1 +
 src/Main.cxx | 13 +++++++++++++
 2 files changed, 14 insertions(+)

diff --git a/NEWS b/NEWS
index f81782417..b04e8cae9 100644
--- a/NEWS
+++ b/NEWS
@@ -2,6 +2,7 @@ ver 0.20.7 (not yet released)
 * database
   - simple: fix false positive directory loop detection with NFS
 * enforce a reasonable minimum audio_buffer_size setting
+* cap buffer_before_play at 80% to prevent deadlock
 * fix random crashes when compiled with clang
 
 ver 0.20.6 (2017/03/10)
diff --git a/src/Main.cxx b/src/Main.cxx
index 5e7610880..a431aa4ec 100644
--- a/src/Main.cxx
+++ b/src/Main.cxx
@@ -340,6 +340,19 @@ initialize_decoder_and_player(const ReplayGainConfig &replay_gain_config)
 					 "than 100 percent, line %i",
 					 param->value.c_str(), param->line);
 		}
+
+		if (perc > 80) {
+			/* this upper limit should avoid deadlocks
+			   which can occur because the DecoderThread
+			   cannot ever fill the music buffer to
+			   exactly 100%; a few chunks always need to
+			   be available to generate silence in
+			   Player::SendSilence() */
+			FormatError(config_domain,
+				    "buffer_before_play is too large (%f%%), capping at 80%%; please fix your configuration",
+				    perc);
+			perc = 80;
+		}
 	} else
 		perc = DEFAULT_BUFFER_BEFORE_PLAY;