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

David Henningsson david.henningsson at canonical.com
Tue Apr 9 08:45:32 CEST 2013

On 04/08/2013 05:47 PM, Lin, Mengdong wrote:
>> -----Original Message-----
>> From: Takashi Iwai [mailto:tiwai at suse.de]
>> Sent: Monday, April 08, 2013 9:50 PM
>> To: David Henningsson
>> Cc: Lin, Mengdong; alsa-devel at alsa-project.org; Girdwood, Liam R
>> Subject: Re: [alsa-devel] [PATCH] ALSA: hda - delay resume haswell hdmi codec
>> in system resume
>> 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.
> This is same as what I observed after S3 or connect HDMI/DP cable after boot, on machines with power_save is '0'.
> Amp-Out vals:  [0x00 0x80]
> Power: setting=D3, actual=D3
> If we set the pin state to D0 and unmute the pin again, HDMI can work. So I still think this is also caused by dependency on Gfx.
> But the controller cannot find the error when it programs the codec to D0
> -  when audio driver programs the codec and pins to D0, HW does not return error
> -  I also added code to check their power state immediately after setting state to D0, HW reports their state did change to D0.
> However, after Gfx driver finishes setting up the display pipeline and enabling audio, the pin's state changed to D3 and get muted, as shown by /proc.
> It seems to me that Gfx HW initialization can override some audio driver settings. So we choose to delay resuming the codec until the unsol event which indicates Gfx is ready.

I've been answering the power_save questions a little bit uncertain so 
far, and that's because I don't really know. I've not investigated power 
management much.

But the person with the hardware reports that this problem happens when 
on AC power only. And that makes sense with your observations about 
power_save - there could very well be something that turns power_save 
off when on AC power and on when on battery power.

So, if it's just a matter of re-initializing the pin, what do you think 
about this solution:

  - Resume as normal (this will enable unsol events)
  - Any time an unsol event comes in, have a haswell specific function 
that checks relevant pins to see that is still in D0 and mute state 
correct. If not, correct it.
  - This check could possibly also be done in the prepare hook for extra 

David Henningsson, Canonical Ltd.

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