From owner-freebsd-current@FreeBSD.ORG Wed Sep 19 05:56:51 2012 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id D71C2106564A; Wed, 19 Sep 2012 05:56:51 +0000 (UTC) (envelope-from sendtomatt@gmail.com) Received: from mail-pb0-f54.google.com (mail-pb0-f54.google.com [209.85.160.54]) by mx1.freebsd.org (Postfix) with ESMTP id A38BD8FC18; Wed, 19 Sep 2012 05:56:51 +0000 (UTC) Received: by pbbrp2 with SMTP id rp2so1822499pbb.13 for ; Tue, 18 Sep 2012 22:56:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:content-type:content-transfer-encoding; bh=d3cQOSxvTk/w0yW6c86pj805MsgRAnkVsf7Vtd7tv1g=; b=m3YR1DwHQ8F38ziZZHbfuQtGxdqyiVDTjX2PgCyGlNGQ4gOzAPVaSBBwMw/Afkti3k Z78Dexc2+ZqluhSZTEc7TpJLZ//ZkpxbetKJmyJxoEn9PJoNgLNB6t6PUCvPjEo0tYmN oIpMaPIc/EGtl2KQGfA4UjBNqa0P0hZ8D/SOSkstUNk2H02kiVjNFMxj3aRC6J+/qR0G fCKaN6ixyhlv65gGT20tgthOA//o57vT3jSHaLUCAuRXAw7YKuS2WtIa18Qvw/AEOPlQ 4g6DEubHDQfuA+wlfNcO7+Kfu8FTky/LOtTeMK/DdRNaHMEeRgdeNM/LAYksthHRj2sL iqeA== Received: by 10.68.189.193 with SMTP id gk1mr4560453pbc.123.1348034205716; Tue, 18 Sep 2012 22:56:45 -0700 (PDT) Received: from flatline.local (70-36-223-239.dsl.dynamic.sonic.net. [70.36.223.239]) by mx.google.com with ESMTPS id vf8sm1254381pbc.27.2012.09.18.22.56.43 (version=SSLv3 cipher=OTHER); Tue, 18 Sep 2012 22:56:44 -0700 (PDT) Message-ID: <50595E93.9080908@gmail.com> Date: Tue, 18 Sep 2012 22:56:35 -0700 From: matt User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:15.0) Gecko/20120912 Thunderbird/15.0.1 MIME-Version: 1.0 To: Doug Barton References: <5059194F.4090002@FreeBSD.org> In-Reply-To: <5059194F.4090002@FreeBSD.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: freebsd-current@FreeBSD.org Subject: Re: squealing/whistling audio X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 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: Wed, 19 Sep 2012 05:56:51 -0000 On 09/18/12 18:01, Doug Barton wrote: > Sometime in the last couple of months an old problem has resurfaced on > HEAD, a sort of squealing/whistling sound in the audio, even without > anything playing. The sound is similar to the wind whistling through > something. > > Before I blindly go off on a bisecting spree, does anyone have a > suggestion as to where I might look? > > Doug > > Electrically that's usually oscillation (too high gain or too much electrical feedback) or an unshielded input. My guess would be that there is an input that is defined and active in software, but is a loose, ungrounded pin in real life. Like a second microphone input on the chip, but not actually connected, would be my guess. Can you try purging out nids that you don't use with loader tunables (set their as to 0)? Or sysctls as reboots aren't as necessary anymore with snd_hda? Maybe something changed in software that is seeing inputs that were not present. Also just try muting all inputs with mixer... Just a guess, but when I hear squealing/whistling/howling I think "analog" before I think "digital"... Matt