From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wu Fengguang Subject: Re: Loud pops from Intel HDA onboard sound, may damage speakers (fwd) Date: Thu, 24 Mar 2011 09:43:50 +0800 Message-ID: <20110324014350.GA8029@localhost> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by alsa0.perex.cz (Postfix) with ESMTP id D9B1924179 for ; Thu, 24 Mar 2011 02:43:55 +0100 (CET) Content-Disposition: inline In-Reply-To: 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: Chris Wilson Cc: alsa-devel@alsa-project.org, matt.jared@intel.com, andy.kopp@intel.com, Takashi Iwai , dan.d.kogan@intel.com, PeiSen Hou List-Id: alsa-devel@alsa-project.org Hi Chris, Would you run http://www.alsa-project.org/alsa-info.sh and email the results? Thanks, Fengguang On Thu, Mar 24, 2011 at 01:35:54AM +0000, Chris Wilson wrote: > ---------- Forwarded message ---------- > Date: Thu, 24 Mar 2011 00:49:55 +0000 (GMT) > From: Chris Wilson > To: Takashi Iwai , PeiSen Hou , > matt.jared@intel.com, andy.kopp@intel.com, dan.d.kogan@intel.com > Subject: Loud pops from Intel HDA onboard sound, may damage speakers > > Dear sirs, > > I'm writing to you as the named contacts in hda_intel.c in the Linux > kernel. Please let me know if I should contact someone else instead. > > I refer to this downstream bug on Ubuntu Launchpad, which I am > hereby taking upstream: > https://bugs.launchpad.net/ubuntu/+source/linux/+bug/184632 > > I have a desktop system (Fujitsu P9900) with the onboard sound > connected to my hi-fi amplifier, driven by snd_hda_intel. The audio > chipset is: > > 00:1b.0 Audio device: Intel Corporation 5 Series/3400 Series Chipset > High Definition Audio (rev 05) > > The sound card outputs loud popping sounds whenever I suspend and > resume it. One of them is loud or severe enough to cause my hi-fi > amplifier to go into automatic shutdown mode, and I'm worried that > it may damage my speakers. > > If I enable power_save=1, as suggested by powertop, then this > happens about 2 seconds after any audio finishes playing as well, so > I suspect it's related to putting the sound card in or out of > suspend mode. > > The pops seem to be happening to others who have this chipset as > well, as seen on the bug report, but they seem mostly to be using > laptops or otherwise not bothered by potential damage to their > speakers. > > I would really appreciate it if you could help me to find a way to > avoid these pops, for example by muting the audio output before > shutting down the DAC? I think it would be great if this could make > it into the standard kernel driver. > > Many thanks in advance, > > Chris Wilson. > -- > _____ __ _ > \ __/ / ,__(_)_ | Chris Wilson Cambs UK | > / (_/ ,\/ _/ /_ \ | Security/C/C++/Java/Ruby/Perl/SQL Developer | > \__/_/_/_//_/___/ | We are GNU : free your mind & your software |