At Thu, 11 Jun 2015 01:12:36 +0300, Mihai Donțu wrote: > > On Wed, 10 Jun 2015 20:23:01 +0200 Takashi Iwai wrote: > > From: Takashi Iwai <ti...@suse.de> > > Subject: [PATCH] ALSA: hda - Reduce click noise at power up > > > > 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. > > > > 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. > > > > Reported-by: Mihai Donțu <mihai.do...@gmail.com> > > Signed-off-by: Takashi Iwai <ti...@suse.de> > > --- > > sound/pci/hda/hda_codec.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > 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; > > } > > > > + if (power_state == AC_PWRST_D0) > > + msleep(10); > > + > > return state; > > } > > > > 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.
OK, then the patch is no-go. We need a bit deeper analysis. About the headphone problem: don't you get the same issue with 4.0.x? Please take alsa-info.sh outputs on both 4.0.x and 4.1 before and after plugging the headphone, and attach the outputs. (Run the script with --no-upload option.) thanks, Takashi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
