[alsa-devel] [PATCH] ALSA: hda - delay resume haswell hdmi codec in system resume

[Takashi Iwai]

At Mon, 08 Apr 2013 15:30:25 +0200,
David Henningsson wrote:
> 
> On 04/08/2013 02:23 PM, Takashi Iwai wrote:
> > At Mon, 08 Apr 2013 14:20:28 +0200,
> > David Henningsson wrote:
> >>
> >> On 04/08/2013 01:59 PM, Takashi Iwai wrote:
> >>> At Mon, 08 Apr 2013 13:35:25 +0200,
> >>> David Henningsson wrote:
> >>>>
> >>>> On 04/08/2013 01:06 PM, Lin, Mengdong wrote:
> >>>>>> -----Original Message-----
> >>>>>> From: Takashi Iwai [mailto:tiwai at suse.de]
> >>>>>> Sent: Monday, April 08, 2013 6:24 PM
> >>>>>> To: David Henningsson
> >>>>>> Cc: Lin, Mengdong; alsa-devel at alsa-project.org
> >>>>>> Subject: Re: [alsa-devel] [PATCH] ALSA: hda - delay resume haswell hdmi codec
> >>>>>> in system resume
> >>>>>>
> >>>>>> At Mon, 08 Apr 2013 11:49:09 +0200,
> >>>>>> David Henningsson wrote:
> >>>>>>>
> >>>>>>> I'm still not understanding this patch.
> >>>>>>>
> >>>>>>> We of course cannot have a situation where HDMI jack detection is not
> >>>>>>> correctly working after S3, which looks like would be the case here?
> >>>>>>
> >>>>>> No.  The patch itself has nothing to do with the HDMI jack detection at all.
> >>>>>> This intrinsic unsol event is (according to Intel) guaranteed to be issued once at
> >>>>>> the audio codec initialization, at least for Haswell.
> >>>>
> >>>> Well, if no process is using the HDMI codec actively, nothing will
> >>>> initialize the resume, and the HDMI codec will not initialized at all, i
> >>>> e, no unsol events enabled in the first place?
> >>>
> >>> No, the intrinsic unsol event that is issued for this seems irrelevant
> >>> from the jack state (i.e. active usage).
> >>>
> >>>> (The counter argument would be; if nobody uses HDMI codec, does it
> >>>> matter that it is not initialized, but I'm unsure if e g "amixer
> >>>> contents" or listeners on legacy /dev/input actually powers up the chip.)
> >>>
> >>> The problem is that the codec resume is always performed no matter
> >>> whether the device is used or not.  This was different in the past but
> >>> it's been changed in that way because there are cases where you need
> >>> to initialize the hardware properly once (e.g. mute-LED toggling).
> >>>
> >>>
> >>>>>>> Second, I just saw on a machine we're working on, the symptoms: one of
> >>>>>>> the pins in D3 and the right channel muted. And this was on a clean
> >>>>>>> boot, not after S3 suspend/resume cycle.
> >>>>>>
> >>>>>> Maybe another problem.  Maybe not.  Does the problem persist if you reload
> >>>>>> the driver (without invocation of alsactl via udev)?
> >>>>>
> >>>>> Hi Takashi and David,
> >>>>>
> >>>>> This is the same dependency issue as after system suspend/resume cycles, with same phenomenon.
> >>>>> I duplicated this error if I boot without an HDMI/DP cable connected and connect the cable later.
> >>>>> Maybe we need to delay codec operations on initialization like in resume case.
> >>>>
> >>>> So it's a problem both on hotplug and S3...
> >>>
> >>> In the case of hotplug, you don't hit the inconsistent power sate
> >>> we're trying to solve.  The graphics has been already powered up.
> >>>
> >>>
> >>>>>>> To look at the problem again: If the problem is that something must be
> >>>>>>> done on the graphics driver side first and then on the audio side,
> >>>>>>> wouldn't the solution be for the video driver and audio driver to
> >>>>>>> communicate somehow?
> >>>>>>
> >>>>>> Yes, the pm domain support is necessary sooner or later, as I already discussed
> >>>>>> shortly with Dave Airlie.  However...
> >>>>>
> >>>>> Liam will propose Gfx driver team to implement a pm domain.
> >>>>>
> >>>>>>> And resume (and possibly init?) would not complete until first the
> >>>>>>> graphics driver has done its resume, and after that, the audio driver.
> >>>>>>> I e, userspace will remain frozen until both drivers have completed a
> >>>>>>> correct resume.
> >>>>>>
> >>>>>> ... the resume problem can't be fixed only by the usual pm domain serialization.
> >>>>>> The graphics initialization for the audio bit is done asynchronously, thus we
> >>>>>> can't guarantee the audio codec is really ready after the graphics driver returns
> >>>>>> from the resume callback.
> >>>>>> It shows as if it's ready (you can turn it to D0) but actually it doesn't change on
> >>>>>> the hardware.  Thus, the serialization with an unsol event wait seems
> >>>>>> mandatory for the time being.
> >>>>>>
> >>>>> It seems so. We have not found better solution now :-(
> >>>>> I've revised the patch for system suspend/resume case. Please review.
> >>>>
> >>>> If this problem can be detected by looking at the pin and finding that
> >>>> it is in D3,
> >>>
> >>> No, you can't see that it's D3.  The controller chip _shows_ it's in
> >>> D0 while it's actually in D3.  That's the problem.
> >>>
> >>> So, this is actually a hardware design bug.  But we need to live with
> >>> that.
> >>
> >> Then I'm not sure it's the same problem; because for me I can see the D3
> >> in the codec proc output.
> >
> > I suppose you didn't set the powersave for it, right?
> 
> AFAIK, powersave remains at upstream default.

The option is overridden by user-space, so checking only the default
value doesn't make any sense :)

> > BTW, the main problem was about the FG node, which you can't judge
> > from the proc output, unfortunately.
> 
> Here's what it looks like for me. Right channel muted and pin in D3.
> 
> Node 0x05 [Pin Complex] wcaps 0x40778d: 8-Channels Digital Amp-Out CP
>    Control: name="HDMI/DP,pcm=3 Jack", index=0, device=0
>    Control: name="IEC958 Playback Con Mask", index=0, device=0
>    Control: name="IEC958 Playback Pro Mask", index=0, device=0
>    Control: name="IEC958 Playback Default", index=0, device=0
>    Control: name="IEC958 Playback Switch", index=0, device=0
>    Control: name="ELD", index=0, device=3
>    Amp-Out caps: ofs=0x00, nsteps=0x00, stepsize=0x00, mute=1
>    Amp-Out vals:  [0x00 0x80]
>    Pincap 0x0b000094: OUT Detect HBR HDMI DP
>    Pin Default 0x18560010: [Jack] Digital Out at Int HDMI
>      Conn = Digital, Color = Unknown
>      DefAssociation = 0x1, Sequence = 0x0
>    Pin-ctls: 0x40: OUT
>    Unsolicited: tag=01, enabled=1
>    Power states:  D0 D3 EPSS
>    Power: setting=D3, actual=D3
>    Connection: 3
>       0x02* 0x03 0x04

Then this might be the different issue.


Takashi