[alsa-devel] Loud pops from Intel HDA onboard sound, may damage speakers (fwd)

[Takashi Iwai]

At Fri, 25 Mar 2011 16:05:48 +0800,
Kailang wrote:
> 
> Hi Takashi,
> 
>  Attachment was the patch that refference by snapshot 2011.03.25.
> 
>    Fixed & Update List:
>     patch_realtek.c
>    - ALC662
>            - Fixed ALC66x pop noise on suspend and resume.
> 
>     This patch that I test on Acer NB. The result is better than before.
>     Could you know how to pull EAPD to low on power down state?

We should add hook alc_shutup().  It's called also at shutdown path.
For example, add spec->shutup callback, and move the eapd and delay
into there.  ALC269 PM changes can be changed similarly.

An open question is how to handle the wake-up (resume) case.

I see you added two delays.  Do they give significant difference?
I'm wondering whether the second delay gives any difference.
The first one is the point just after power-state change, so it
can influence.  But the second delay is for...?


thanks,

Takashi

> 
> Best Regards,
> Kailang
> 
> ----- Original Message ----- 
> From: Takashi Iwai
> To: Kailang
> Cc: Chris Wilson ; Wu Fengguang ; Pshou ; andy.kopp at intel.com ; 
> dan.d.kogan at intel.com ; alsa-devel at alsa-project.org
> Sent: Friday, March 25, 2011 3:52 PM
> Subject: Re: Loud pops from Intel HDA onboard sound, may damage speakers 
> (fwd)
> 
> 
> At Fri, 25 Mar 2011 15:43:55 +0800,
> Kailang wrote:
> >
> >
> > > ALC269 has some workarounds using COEF magic.  Maybe there is a
> > > similar trick for ALC663.  Kailang, do you know of it?
> >
> > ALC663 has no this control bits like ALC269.
> > But it can use EAPD to control it.
> > The EAPD pull low before suspend.
> > When the resume back, run the EAPD to pull high first.
> >
> > I could send the patch for you later.
> 
> Thanks.
> 
> I vaguely remember that this was tried for other codecs but didn't
> give good results (rather worse).  Anyway let's check again.
> 
> 
> Takashi
> 
> >
> > Kailang
> >
> > ----- Original Message ----- 
> > From: Takashi Iwai
> > To: Chris Wilson
> > Cc: Wu Fengguang ; Pshou ; Kailang ; andy.kopp at intel.com ;
> > dan.d.kogan at intel.com ; alsa-devel at alsa-project.org
> > Sent: Friday, March 25, 2011 3:00 PM
> > Subject: Re: Loud pops from Intel HDA onboard sound, may damage speakers
> > (fwd)
> >
> >
> > At Thu, 24 Mar 2011 22:41:47 +0000 (GMT),
> > Chris Wilson wrote:
> > >
> > > Hi Takashi and all,
> > >
> > > On Thu, 24 Mar 2011, Takashi Iwai wrote:
> > >
> > > >>> Does this happen with 2.6.38 kernel, too?
> > > >>
> > > >> I have not tried yet, do you have reason to think it may have changed
> > > >> since 2.6.32?
> > > >
> > > > Lots of changes since 2.6.32.  I won't be surprised if any of them 
> > > > hits.
> > > >
> > > >> Can I build just the sound driver without replacing the whole kernel?
> > > >
> > > > You can try alsa-driver tarball.
> > >
> > > Unfortunately, I can confirm that stock 2.6.38 does NOT resolve the pops
> > > on suspend and resume.
> >
> > OK, then did you try to set option power_save_controller=0 for
> > snd-hda-intel?
> >
> > ALC269 has some workarounds using COEF magic.  Maybe there is a
> > similar trick for ALC663.  Kailang, do you know of it?
> >
> >
> > thanks,
> >
> > Takashi
> >
> > ------Please consider the environment before printing this e-mail.
> >