linux-kernel - Re: [BUG] [REGRESSION] [BISECTED] -rc1 breaks audio over HDMI for i915

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Date:	Mon, 22 Feb 2016 11:24:05 +0100
From:	Martin Kepplinger <martink@...teo.de>
To:	Takashi Iwai <tiwai@...e.de>
Cc:	david.henningsson@...onical.com, han.lu@...el.com,
	libin.yang@...el.com, treding@...dia.com, perex@...ex.cz,
	alsa-devel@...a-project.org, linux-kernel@...r.kernel.org
Subject: Re: [BUG] [REGRESSION] [BISECTED] -rc1 breaks audio over HDMI for
 i915

Am 2016-02-12 um 17:16 schrieb Takashi Iwai:
> On Fri, 12 Feb 2016 16:54:44 +0100,
> Martin Kepplinger wrote:
>>
>> Am 2016-02-12 um 14:49 schrieb Takashi Iwai:
>>> On Fri, 12 Feb 2016 14:09:36 +0100,
>>> Martin Kepplinger wrote:
>>>>
>>>> Am 2016-02-11 um 10:06 schrieb Takashi Iwai:
>>>>> On Wed, 10 Feb 2016 18:21:11 +0100,
>>>>> Martin Kepplinger wrote:
>>>>>>
>>>>>> Am 2016-02-09 um 12:44 schrieb Takashi Iwai:
>>>>>>> On Tue, 09 Feb 2016 07:34:48 +0100,
>>>>>>> Martin Kepplinger wrote:
>>>>>>>>
>>>>>>>> The following change:
>>>>>>>>
>>>>>>>> 788d441 ALSA: hda - Use component ops for i915 HDMI/DP audio jack handling
>>>>>>>>
>>>>>>>> breaks audio over HDMI on my snd_hda_intel laptop. It is the first bad
>>>>>>>> commit.
>>>>>>>>
>>>>>>>> This was merged for -rc1 and isn't fixed until now, so I got nervous.
>>>>>>>> There are
>>>>>>>> no errors in the log that stand out. I'm no sound or alsa developer, and
>>>>>>>> just reverting it isn't easy since there is stuff depending on this.
>>>>>>>>
>>>>>>>> I'm happy to test possible fixes and hope v4.5 not to ship with such a big
>>>>>>>> regression ;)
>>>>>>>
>>>>>>> Could you give a bit more detail about your hardware?  At best, give
>>>>>>> alsa-info.sh output (run with --no-upload option).  Also, give the
>>>>>>> output of dmesg, too.
>>>>>>>
>>>>>>> In addition, what shows /proc/asound/card*/eld#*.* files?  Does any of
>>>>>>> it show the proper connection state and ELD?
>>>>>>
>>>>>> alsa-info and dmesg are appended, and
>>>>>>
>>>>>> root@...top:/home/martin/dev# cat /proc/asound/card*/eld#*
>>>>>> monitor_present		0
>>>>>> eld_valid		0
>>>>>
>>>>> OK, then could you put some debug print in intel_pin_eld_notify() in
>>>>> sound/pci/hda/patch_hdmi.c?  This is the callback to be called by i915
>>>>> driver at enabling / disabling HDMI/DP audio.
>>>>
>>>> intel_pin_eld_notify() is called during HDMI plugin with
>>>>
>>>> audio_ptr: ffff880242ea8800, port 1
>>>>
>>>> and doesn't return early.
>>>
>>> OK, so it was processed but the ELD wasn't updated by some reason.
>>>
>>>>> (Also, to be sure, check whether snd_hdac_i915_register_notifier() in
>>>>>  sound/hda/hda_i915.c is called, too.)
>>>>
>>>> snd_hdac_i915_register_notifier() is called during boot.
>>>>
>>>>>
>>>>> If intel_pin_eld_notify() is registered but never called, it implies
>>>>> something wrong in i915 driver side.  If it gets called, we need to
>>>>> track down: what port value was passed there, and how
>>>>> hdmi_present_sense() and sync_eld_via_acomp() behave there.
>>>>
>>>> I'll try to look at said path, if you have no other idea in the meantime.
>>>
>>> Put some debug prints in sync_eld_via_acomp(), e.g. check whether
>>> snd_hdac_acomp_get_eld() returns an error or snd_hdmi_parse_eld()
>>> returns an error.  If you got an error, track down more deeply.
>>>
>>> For example, the former function is defined in sound/hda/hdac_i915.c,
>>> and it calls the function i915_audio_component_get_eld() in
>>> drivers/gpu/drm/i915/intel_audio.c.  You can follow what returns an
>>> error.
>>>
>>> Similarly, the latter function is defined in sound/pci/hda/hda_eld.c.
>>> Usually you see a kernel message for parse errors, so I guess this
>>> isn't the case, though.
>>>
>>
>> no error in either of the functions. size is always 0, after boot and
>> after HDMI plugin. is that normal?
> 
> No, it means that no connection is reported back.  Check the call of
> i915_audio_component_get_eld() as mentioned in the above.
> Does it return 0?  Also I suppose monitor_present is set to false?
> If so, it implies that intel_audio_codec_enable() isn't called.
> 
> When the above is true, boot with drm.debug=0x0e, and give the kernel
> messages.
> 

The above is true and -rc5 didn't fix the problem. I append "dmesg|grep
drm" with drm.debug=0x0e. HDMI is plugged in at about 90 seconds in.

                        martin



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