From f3f194293a217aac189e8c5dff21473c9148ddcb Mon Sep 17 00:00:00 2001
From: Mathijs van de Nes <git@mathijs.vd-nes.nl>
Date: Sun, 28 Feb 2016 17:01:13 +0100
Subject: [PATCH] Fix underflow detection for alsa

The old method always returned _RUNNING on some machines.
This new method seems to produce the expected behaviour.

Note: -32 is probably -EPIPE, but the appropriate constant was not
available at this time.
---
 src/alsa/mod.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/alsa/mod.rs b/src/alsa/mod.rs
index f39e31f..80ba236 100644
--- a/src/alsa/mod.rs
+++ b/src/alsa/mod.rs
@@ -317,8 +317,8 @@ impl Voice {
     pub fn underflowed(&self) -> bool {
         let channel = self.channel.lock().expect("channel underflow");
 
-        let state = unsafe { alsa::snd_pcm_state(*channel) };
-        state == alsa::SND_PCM_STATE_XRUN
+        let available = unsafe { alsa::snd_pcm_avail(*channel) };
+        available == -32
     }
 }