From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rene Herman Subject: Re: [PATCH] es1968: fix jitter on some maestro cards Date: Tue, 01 Apr 2008 00:24:43 +0200 Message-ID: <47F164AB.5040009@keyaccess.nl> References: <20080329234943.GA2899@slappy> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="------------010102030003060405030903" Return-path: Received: from smtpq1.tilbu1.nb.home.nl (smtpq1.tilbu1.nb.home.nl [213.51.146.200]) by alsa0.perex.cz (Postfix) with ESMTP id CF9F524846 for ; Tue, 1 Apr 2008 00:22:57 +0200 (CEST) In-Reply-To: <20080329234943.GA2899@slappy> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: alsa-devel-bounces@alsa-project.org Errors-To: alsa-devel-bounces@alsa-project.org To: Andreas Mueller Cc: tiwai@suse.de, ALSA devel , linux-kernel@vger.kernel.org, MatzeBraun@gmx.de List-Id: alsa-devel@alsa-project.org This is a multi-part message in MIME format. --------------010102030003060405030903 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit On 30-03-08 00:49, Andreas Mueller wrote: > 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. > I am barely used to driver-development so please take a look (esp. the channel > parameters), nevertheless it completely works for me. > > Without this patch most of the stereo audio gets out of sync and really > distorted (oss-emulation with mplayer at 48000khz worked somehow). > > CCed to those listed in the .c file. Added the alsa-devel list (and re-attached the patch). My TerraTec DMX (ESS Canyon3D, ES1970MS-3D) doesn't need this but doesn't seem to suffer from it either. Otherwise no idea about this. Rene. --------------010102030003060405030903 Content-Type: text/plain; name="es1968_jitter.patch" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="es1968_jitter.patch" --- sound/pci/es1968.c.old 2008-03-29 19:17:16.771116317 +0100 +++ sound/pci/es1968.c 2008-03-30 00:14:35.363057160 +0100 @@ -1816,7 +1816,24 @@ 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 */ @@ -1937,8 +1954,11 @@ 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) { --------------010102030003060405030903 Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Alsa-devel mailing list Alsa-devel@alsa-project.org http://mailman.alsa-project.org/mailman/listinfo/alsa-devel --------------010102030003060405030903--