From 514fd1eee848c3a81298fa34422df3a98027b322 Mon Sep 17 00:00:00 2001
From: Pierre-Louis Bossart <pierre-louis.bossart@intel.com>
Date: Thu, 29 Apr 2010 10:48:11 -0500
Subject: add rewind-safeguard parameter

Rewinding the ring buffer completely causes audible issues with DMAs.
Previous solution didn't work with tsched=0, and used tsched_watermark
for guardband, which isn't linked to hardware and could become really high
if underflows occurred.

Added separate parameter that can be tuned to hardware limitations and size
of DMA bursts.
---
 src/modules/alsa/module-alsa-sink.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

(limited to 'src/modules/alsa/module-alsa-sink.c')

diff --git a/src/modules/alsa/module-alsa-sink.c b/src/modules/alsa/module-alsa-sink.c
index 3aa89b2a..a73274fd 100644
--- a/src/modules/alsa/module-alsa-sink.c
+++ b/src/modules/alsa/module-alsa-sink.c
@@ -54,7 +54,8 @@ PA_MODULE_USAGE(
         "tsched_buffer_size=<buffer size when using timer based scheduling> "
         "tsched_buffer_watermark=<lower fill watermark> "
         "ignore_dB=<ignore dB information from the device?> "
-        "control=<name of mixer control>");
+        "control=<name of mixer control>"
+        "rewind_safeguard=<number of bytes that cannot be rewound");
 
 static const char* const valid_modargs[] = {
     "name",
@@ -74,6 +75,7 @@ static const char* const valid_modargs[] = {
     "tsched_buffer_watermark",
     "ignore_dB",
     "control",
+    "rewind_safeguard",
     NULL
 };
 
-- 
cgit