From owner-freebsd-current@FreeBSD.ORG Wed Mar 26 17:28:57 2003 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 9852337B404 for ; Wed, 26 Mar 2003 17:28:57 -0800 (PST) Received: from puma.icir.org (puma.icir.org [192.150.187.73]) by mx1.FreeBSD.org (Postfix) with ESMTP id 13F9643F75 for ; Wed, 26 Mar 2003 17:28:57 -0800 (PST) (envelope-from hodson@puma.icir.org) Received: from puma.icir.org (localhost [127.0.0.1]) by puma.icir.org (8.12.3/8.12.3) with ESMTP id h2R1SsAT090245; Wed, 26 Mar 2003 17:28:55 -0800 (PST) (envelope-from hodson@puma.icir.org) Message-Id: <200303270128.h2R1SsAT090245@puma.icir.org> X-Mailer: exmh version 2.5 07/13/2001 with nmh-1.0.3 From: Orion Hodson To: "Kevin Oberman" In-Reply-To: <20030326210223.9B74B5D07@ptavv.es.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Wed, 26 Mar 2003 17:28:54 -0800 Sender: hodson@icir.org X-Spam-Status: No, hits=-1.7 required=5.0 tests=AWL,IN_REP_TO,MSG_ID_ADDED_BY_MTA_3 autolearn=ham version=2.50 X-Spam-Level: X-Spam-Checker-Version: SpamAssassin 2.50 (1.173-2003-02-20-exp) cc: current@freebsd.org Subject: Re: AC97 sound problems with current X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 27 Mar 2003 01:28:58 -0000 Kevin Oberman writes: | | After upgrading my laptop from STABLE to CURRENT on 3/14 I have been | having problems with GnomeMeeting. Often the sound is badly broken with | 'spurts' of sound with silent gaps in between. This was never the case | with STABLE. Other times it's fine. | | When I looked at my dmesg output I noticed some changes between STABLE | and CURRENT for the pcm0 device. Under STABLE I only got two messages: | pcm0: port 0x18c0-0x18ff,0x1c00-0x1cff irq 11 at device 31.5 on pci0 | pcm0: | Under CURRENT I get a third: | | pcm0: measured ac97 link rate at 512000000 Hz There is a calibration step in the driver to determine the clock rate of the AC97 link. What you are seeing is the calibration step failing and setting a bogus ac97 link rate. I took a cursory look a couple of weeks back and it smelt like the timecounter initialization point changed, but haven't gotten around to looking closer and fixing the driver. It's on the todo list... I've also been wondering if it's possible to ditch the calibration entirely, but this is an involved AC97 question and I don't have easy access to the relevant h/w and it's a different q. Anyway, whilst it remains broken you can set the ac97 clock rate by hand. The sysctl variable hw.snd.pcmX.ac97rate exists specifically for times when the calibration test fails (X = 0 if no other cards installed). Depending on which clock source is being used by the codec you'll want to set the variable to 48000 or around 55913. YMMV, but kldloading the driver rather than having it compiled into the kernel will probably result in the correct calibration. - Orion