From mboxrd@z Thu Jan 1 00:00:00 1970 From: Takashi Iwai Subject: Re: Audio crackles with 4.1-rc1 Date: Tue, 28 Apr 2015 16:43:00 +0200 Message-ID: References: <20150428112156.GQ10148@earth.li> <20150428123518.GU10148@earth.li> Mime-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Jonathan McDowell Cc: alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org List-Id: alsa-devel@alsa-project.org At Tue, 28 Apr 2015 15:05:20 +0200, Takashi Iwai wrote: > > At Tue, 28 Apr 2015 13:35:18 +0100, > Jonathan McDowell wrote: > > > > On Tue, Apr 28, 2015 at 02:00:17PM +0200, Takashi Iwai wrote: > > > At Tue, 28 Apr 2015 12:21:57 +0100, > > > Jonathan McDowell wrote: > > > > > > > > Having upgraded to 4.1-rc1 from 4.0 I'm now hearing audio crackles at > > > > regular intervals. I'm fairly sure this is due to the HDA power save as > > > > once audio is playing things are fine, it's just when starting to play > > > > audio that I hear the crackle. > > > > > > > > System is a Dell Latitude E7240. I haven't tried a bisect yet but will > > > > attempt to find some time to do so in the next few days. It looks like > > > > there have been some changes in sound/hda/ between 4.0 + 4.1-rc1 so I'll > > > > concentrate on those first. > > > > > > > There are lots of code changes and enhancements wrt power saving in > > > 4.1, and bisection won't help so much, I'm afraid. > > > > > > First off, check the device status while you hear crackles. > > > Is the codec in runtime suspend (aka power save)? This can be seen in > > > /sys/bus/hdaudio/devices/*/power/runtime_status. Then check the > > > runtime status of the controller, too, found in > > > /sys/class/sound/card?/device/power/runtime_status. > > > > The cracking is definitely happening with the transition from suspended > > to active: > > > > /sys/class/sound/card0/device/power/runtime_status:suspended > > /sys/class/sound/card1/device/power/runtime_status:active > > /sys/bus/hdaudio/devices/hdaudioC0D0/power/runtime_status:suspended > > /sys/bus/hdaudio/devices/hdaudioC1D0/power/runtime_status:active > > > > card1 + C1D0 were suspended, I hit delete in a terminal to force a > > terminal bell, got the crackle and the state changed to active as above. > > Ah, so it's a click noise that happens only once per runtime PM > transition? I thought it were constant crackling noises from your > description ("regular intervals"). > > In anyway, please give alsa-info.sh output on both 4.0 and 4.1. Also, does the click noise occur only at powering up, and not at powering down? Takashi