From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mihai =?UTF-8?B?RG9uyJt1?= Subject: Re: Audio crackles with 4.1-rc1 Date: Thu, 11 Jun 2015 01:12:36 +0300 Message-ID: <20150611011236.53bcd1fd@mdontu-l> References: <20150429112859.GY10148@earth.li> <20150430150131.GA10148@earth.li> <20150502150513.GF10148@earth.li> <20150519161911.GD28070@earth.li> <20150519215310.GF28070@earth.li> <20150610131755.0b906783@mdontu-l.dsd.bitdefender.biz> <20150610134135.327e2bdc@mdontu-l.dsd.bitdefender.biz> <20150610144551.4578ee99@mdontu-l.dsd.bitdefender.biz> <20150610192202.0e987fd0@mdontu-l.dsd.bitdefender.biz> <20150610194303.3b82609d@mdontu-l.dsd.bitdefender.biz> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Takashi Iwai Cc: Jonathan McDowell , alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org List-Id: alsa-devel@alsa-project.org On Wed, 10 Jun 2015 20:23:01 +0200 Takashi Iwai wrote: > From: Takashi Iwai > Subject: [PATCH] ALSA: hda - Reduce click noise at power up >=20 > Some machines suffer from click noises at power up with the recent > kernels, and this seems triggered at the power transition and the > immediate verb executions. As a workaround, put a short delay (10ms) > right after the D0 transition. >=20 > There are a few places that have the same kind of delays, especially > in the resume path. I guess they can be removed (or reduced) after > this patch. But, since the delay is relatively small, let's do it > later as a cleanup. >=20 > Reported-by: Mihai Don=C8=9Bu > Signed-off-by: Takashi Iwai > --- > sound/pci/hda/hda_codec.c | 3 +++ > 1 file changed, 3 insertions(+) >=20 > diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c > index b7782212dd64..38f5509ee52f 100644 > --- a/sound/pci/hda/hda_codec.c > +++ b/sound/pci/hda/hda_codec.c > @@ -3077,6 +3077,9 @@ static unsigned int hda_set_power_state(struct = hda_codec *codec, > break; > } > =20 > + if (power_state =3D=3D AC_PWRST_D0) > + msleep(10); > + > return state; > } > =20 I take back my previous observations. I was at work and did not have access to headphones (one of those days). Now I'm at home, it's 1 AM, very quiet, and I notice the following: * on speakers: the click reproduces but with _very_ low amplitude; msleep(100) is unnoticeable, but msleep(10) is, barely; * on headphones: the moment I plug them I hear a loud static sound (like an old, untuned AM radio). If I play something, the static disappears. If I pause, the static returns after ~15s. --=20 Mihai Don=C8=9Bu