The patch titled
es1968: fix jitter on some maestro cards
has been added to the -mm tree. Its filename is
es1968-fix-jitter-on-some-maestro-cards.patch
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The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: es1968: fix jitter on some maestro cards
From: Andreas Mueller <andreas@xxxxxxxxxxxxxxxxxx>
This patch suppresses jitter on several Maestro cards in stereo mode (ALSA of
course).
The patch is also incorporated in the *BSD drivers where I "ported" it from.
Without this patch most of the stereo audio gets out of sync and really
distorted (oss-emulation with mplayer at 48000khz worked somehow).
Cc: Rene Herman <rene.herman@xxxxxxxxxxxx>
Cc: Jaroslav Kysela <perex@xxxxxxx>
Cc: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
sound/pci/es1968.c | 22 +++++++++++++++++++++-
1 file changed, 21 insertions(+), 1 deletion(-)
diff -puN sound/pci/es1968.c~es1968-fix-jitter-on-some-maestro-cards sound/pci/es1968.c
--- a/sound/pci/es1968.c~es1968-fix-jitter-on-some-maestro-cards
+++ a/sound/pci/es1968.c
@@ -1815,6 +1815,23 @@ snd_es1968_pcm(struct es1968 *chip, int
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
@@ -1936,8 +1953,11 @@ static irqreturn_t snd_es1968_interrupt(
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) {
_
Patches currently in -mm which might be from andreas@xxxxxxxxxxxxxxxxxx are
es1968-fix-jitter-on-some-maestro-cards.patch
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