Dear Takashi,


On 02/13/19 16:56, Takashi Iwai wrote:
> On Wed, 13 Feb 2019 16:42:19 +0100,
> Paul Menzel wrote:

>> On 02/13/19 16:12, Takashi Iwai wrote:
>>> On Wed, 13 Feb 2019 15:58:44 +0100,
>>> Paul Menzel wrote:
>>>>
>>>>> Why the i915 driver gets initialized *so late*?
>>>>
>>>> Maybe, because it’s built as a module?
>>>>
>>>> ```
>>>> $ grep I915 /boot/config-4.20.8.mx64.245 
>>>> CONFIG_DRM_I915=m
>>>> # CONFIG_DRM_I915_ALPHA_SUPPORT is not set
>>>> CONFIG_DRM_I915_CAPTURE_ERROR=y
>>>> CONFIG_DRM_I915_COMPRESS_ERROR=y
>>>> CONFIG_DRM_I915_USERPTR=y
>>>> # CONFIG_DRM_I915_GVT is not set
>>>> CONFIG_SND_HDA_I915=y
>>>> ```
>>>
>>> That explains.  You built the HD-audio as built-in while the graphics
>>> as module.  This makes the binding impossible at the time of sound
>>> driver initialization.
>>>
>>> If you build the graphics driver as a module, built the sound driver
>>> also as a module.

I tried that now, but `SND_HDA_I915` is just a boolean and no tristate.

    config SND_HDA_I915
            bool
            select SND_HDA_COMPONENT

Then, I built the HDA subsystem as a module, but that also did not help.
The DRM subsystem is started after the HD-audio subsystem.

```
$ grep -e SND_HDA= -e SND_HDA_INTEL /boot/config-4.20.8.mx64.245 
CONFIG_SND_HDA=m
CONFIG_SND_HDA_INTEL=m
$ dmesg
[…]
[   12.465329] snd_hda_intel 0000:00:1f.3: couldn't bind with audio component
[   12.474968] snd_hda_codec_realtek hdaudioC0D0: autoconfig for ALC671: line_outs=1 (0x21/0x0/0x0/0x0/0x0) type:line
[   12.475702] snd_hda_codec_realtek hdaudioC0D0:    speaker_outs=1 (0x17/0x0/0x0/0x0/0x0)
[   12.476368] snd_hda_codec_realtek hdaudioC0D0:    hp_outs=1 (0x14/0x0/0x0/0x0/0x0)
[   12.476953] snd_hda_codec_realtek hdaudioC0D0:    mono: mono_out=0x0
[   12.477421] snd_hda_codec_realtek hdaudioC0D0:    inputs:
[   12.477837] snd_hda_codec_realtek hdaudioC0D0:      Front Mic=0x19
[   12.478252] snd_hda_codec_realtek hdaudioC0D0:      Rear Mic=0x18
[   12.478708] snd_hda_codec_realtek hdaudioC0D0:      Line=0x1a
[   12.489431] snd_hda_codec_hdmi hdaudioC0D2: No i915 binding for Intel HDMI/DP codec
[   12.490170] hdaudio hdaudioC0D2: Unable to bind the codec
[   12.490867] input: HDA Intel PCH Front Mic as /devices/pci0000:00/0000:00:1f.3/sound/card0/input6
[   12.491830] input: HDA Intel PCH Rear Mic as /devices/pci0000:00/0000:00:1f.3/sound/card0/input7
[   12.492599] input: HDA Intel PCH Line as /devices/pci0000:00/0000:00:1f.3/sound/card0/input8
[   12.493268] input: HDA Intel PCH Line Out as /devices/pci0000:00/0000:00:1f.3/sound/card0/input9
[   12.493960] input: HDA Intel PCH Front Headphone as /devices/pci0000:00/0000:00:1f.3/sound/card0/input10
[   15.000998] [drm] Replacing VGA console driver
[…]
```

Please find the messages attached.

>> Can this be enforced by the Kconfig configuration?
> 
> This is the restriction only needed if i915 HDMI audio is used, so you
> can't stop the configuration statically.  Your setup would still work
> except for HDMI, for example.

Understood.

>> If not, should the warning/error message be extended with this hint?
> 
> Possible, but why such a weird configuration at the first place...?

Unfortunately, it comes down to historical reasons and ignorance.


Kind regards,

Paul