On 03-04-08 20:54, akpm@linux-foundation.org wrote:
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
[ ... ]
Subject: es1968: fix jitter on some maestro cards From: Andreas Mueller andreas@stapelspeicher.org
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@keyaccess.nl Cc: Jaroslav Kysela perex@suse.cz Cc: Takashi Iwai tiwai@suse.de Signed-off-by: Andrew Morton akpm@linux-foundation.org
Tested-By: Rene Herman rene.herman@gmail.com
on a TerraTec DMX (ESS Canyon3D, ES1970MS-3D) which doesn't need this but doesn't seem to be suffering from it either. No idea about this otherwise.
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);}
Rene.