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

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Message-ID: <56CC9257.2050704@posteo.de>
Date:	Tue, 23 Feb 2016 18:09:43 +0100
From:	Martin Kepplinger <martink@...teo.de>
To:	Takashi Iwai <tiwai@...e.de>
Cc:	intel-gfx@...ts.freedesktop.org, 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 2016-02-23 um 17:57 schrieb Takashi Iwai:
> On Mon, 22 Feb 2016 22:37:28 +0100,
> Martin Kepplinger wrote:
>>
>> Am 2016-02-22 um 20:10 schrieb Takashi Iwai:
>>> On Mon, 22 Feb 2016 19:58:18 +0100,
>>> Martin Kepplinger wrote:
>>>>
>>>> Am 2016-02-22 um 15:12 schrieb Takashi Iwai:
>>>>> On Mon, 22 Feb 2016 15:02:56 +0100,
>>>>> Martin Kepplinger wrote:
>>>>>>> And how about my questions in the previous mail?  Does
>>>>>>> i915_audio_component_get_eld() is called and returns 0?
>>>>>>> And is monitor_present set true or false?
>>>>>>
>>>>>> i915_audio_component_get_eld() returns 0 and monitor_present is 0.
>>>>>>>
>>>>>>> If i915_audio_component_get_eld() is called but returns zero, track
>>>>>>> the code flow there.  It means either intel_encoder is NULL or
>>>>>>> intel_dig_port->audio_connector is NULL.
>>>>>>
>>>>>> intel_dig_port->audio_connector is NULL!
>>>>>>
>>>>>> (when called during boot and during HDMI plugin)
>>>>>
>>>>> Interesting.  The relevant code flow should be like:
>>>>>
>>>>>   intel_audio_codec_enable()
>>>>>   -> acomp->audio_ops->pin_eld_notify()
>>>>>     -> intel_pin_eld_notify()
>>>>>       -> check_presence_and_report()
>>>>>         -> hdmi_present_sense()
>>>>> 	  -> sync_eld_via_acomp()
>>>>> 	    -> snd_hdac_acomp_get_eld()
>>>>> 	      -> i915_audio_component_get_eld()
>>>>>
>>>>> So, at first, check whether intel_dig_port in both
>>>>> intel_audio_codec_enable() and i915_audio_component_get_eld() points
>>>>> to the same object address.  The audio_connector must be set in
>>>>> intel_audio_codec_enable(), thus basically it must be non-NULL at
>>>>> i915_audio_component_get_eld(), too.
>>>>>
>>>>
>>>> intel_dig_port is *not* the same object in these 2 places. During
>>>> plugin, see:
>>>>
>>>> [  146.934091] in intel_audio_codec_enable: intel_dig_port is
>>>> ffff8800a1f54000
>>>> [  146.934121] in i915_audio_component_get_eld: intel_dig_port is
>>>> ffff880244f7d000
>>>>
>>>> sorry for the slow responses. I'll try to go back that direction unless
>>>> again someone comes up with other suggestions.
>>>
>>> Thanks, this makes sense.  It implies that the digital port mapping is
>>> somehow wrong.  There are three places setting dig_port_map[], one in
>>> intel_ddi_init(), one in intel_dp_init() and another in
>>> intel_hdmi_init().  Try to check which function creates which object
>>> assigned to which port number, together with drm.debug=0x0e debug
>>> messages.
>>>
>> without using drm.debug=0x0e, but by printing the kmalloc'ed objects in
>> those 3 functions with ports, I found:
>>
>> 2 of them are running, only during boot:
>>
>> [    2.322865] intel_hdmi_init: intel_dig_port is ffff880242564000  port 1
>> [    2.322999] intel_dp_init: intel_dig_port is ffff880242f30000  port 1
>>
>> is is correct for them to have both port 1? Any more ideas?
> 
> Adding intel-gfx ML to Cc.

yes thanks, maybe people there have noticed this too. I can't be the
only one.

> 
> Martin, is the machine SandyBridge or IvyBridge?

SandyBridge.

> 
> In anyway it's PCH_SPLIT and there can call both intel_hdmi_init() and 
> intel_dp_init() for the same port although both functions map
> intel_dig_port[].  The assumption of intel_dig_port[] reverse mapping
> is that there is only a single intel_dig_port assigned to a port, but
> this doesn't look correct...
> 
> 
> Takashi
>