From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753378AbYC2Xyy (ORCPT ); Sat, 29 Mar 2008 19:54:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751787AbYC2Xyp (ORCPT ); Sat, 29 Mar 2008 19:54:45 -0400 Received: from smtprelay07.ispgateway.de ([80.67.29.7]:49871 "EHLO smtprelay07.ispgateway.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751211AbYC2Xyp (ORCPT ); Sat, 29 Mar 2008 19:54:45 -0400 X-Greylist: delayed 327 seconds by postgrey-1.27 at vger.kernel.org; Sat, 29 Mar 2008 19:54:44 EDT Date: Sun, 30 Mar 2008 00:49:44 +0100 From: Andreas Mueller To: linux-kernel@vger.kernel.org Cc: MatzeBraun@gmx.de, tiwai@suse.de Subject: [PATCH] es1968: fix jitter on some maestro cards Message-ID: <20080329234943.GA2899@slappy> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="CE+1k2dSO48ffgeK" Content-Disposition: inline User-Agent: Mutt/1.5.17 (2007-11-01) X-Df-Sender: 399301 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --CE+1k2dSO48ffgeK Content-Type: text/plain; charset=us-ascii Content-Disposition: inline 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. Yours sincerely, Andreas Mueller. --CE+1k2dSO48ffgeK Content-Type: text/plain; charset=us-ascii 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) { --CE+1k2dSO48ffgeK--