From d78780c74f03955caa658fd195f759e3aab2c9d9 Mon Sep 17 00:00:00 2001
From: Andreas Mueller <andreas@stapelspeicher.org>
Date: Mon, 14 Apr 2008 13:08:05 +0200
Subject: [PATCH] --- yaml --- r: 92191 b: refs/heads/master c:
 f24bfa53dab478e1bde2d7fd39d3c1a69dc518f1 h: refs/heads/master i:   92189:
 f624b6ebc3e160090fabde1681e828fab57e683c   92187:
 7c35d7827238e1cd4b217ecb759bdf68941fc171   92183:
 fed1b3b097adeb47f2763d5e74794977941cab8d   92175:
 2fc4fb0be7e6413c0500899c8ea2b7cd20fd9667   92159:
 1c9e807f78ea6b5cf9ccff09944301797fea37b9 v: v3

---
 [refs]                   |  2 +-
 trunk/sound/pci/es1968.c | 22 +++++++++++++++++++++-
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/[refs] b/[refs]
index 7450e3c55d77..b52b5093f5ff 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 62cef8212ffa9df3e6c5b358ea2382d90489d590
+refs/heads/master: f24bfa53dab478e1bde2d7fd39d3c1a69dc518f1
diff --git a/trunk/sound/pci/es1968.c b/trunk/sound/pci/es1968.c
index 67f03264f871..f8f3bb662d17 100644
--- a/trunk/sound/pci/es1968.c
+++ b/trunk/sound/pci/es1968.c
@@ -1827,6 +1827,23 @@ snd_es1968_pcm(struct es1968 *chip, int device)
 
 	return 0;
 }
+/*
+ * suppress jitter on some maestros when playing stereo
+ */
+static void snd_es1968_suppress_jitter(struct es1968 *chip, struct esschan *es)
+{
+	unsigned int cp1;
+	unsigned int cp2;
+	unsigned int diff;
+
+	cp1 = __apu_get_register(chip, 0, 5);
+	cp2 = __apu_get_register(chip, 1, 5);
+	diff = (cp1 > cp2 ? cp1 - cp2 : cp2 - cp1);
+
+	if (diff > 1) {
+		__maestro_write(chip, IDR0_DATA_PORT, cp1);
+	}
+}
 
 /*
  * update pointer
@@ -1948,8 +1965,11 @@ static irqreturn_t snd_es1968_interrupt(int irq, void *dev_id)
 		struct esschan *es;
 		spin_lock(&chip->substream_lock);
 		list_for_each_entry(es, &chip->substream_list, list) {
-			if (es->running)
+			if (es->running) {
 				snd_es1968_update_pcm(chip, es);
+				if (es->fmt & ESS_FMT_STEREO)
+					snd_es1968_suppress_jitter(chip, es);
+			}
 		}
 		spin_unlock(&chip->substream_lock);
 		if (chip->in_measurement) {