Re: [PATCH v2 2/4] ASoC: codecs: hda: Skip HDMI/DP registration if i915 is missing

[Cezary Rojewski <cezary.rojewski@intel.com>]

On 2024-02-23 3:44 PM, Takashi Iwai wrote:
> On Fri, 23 Feb 2024 12:46:24 +0100,
> Cezary Rojewski wrote:
>>
>> If i915 does not support given platform but the hardware i.e.: HDAudio
>> codec is still there, the codec-probing procedure will succeed for such
>> device but the follow up initialization will always end up with -ENODEV.
>>
>> While bus could filter out address '2' which Intel's HDMI/DP codecs
>> always enumerate on, more robust approach is to check for i915 presence
>> before registering display codecs.
>>
>> Signed-off-by: Cezary Rojewski <cezary.rojewski@intel.com>
>> ---
>>   sound/soc/codecs/hda.c | 5 +++++
>>   1 file changed, 5 insertions(+)
>>
>> diff --git a/sound/soc/codecs/hda.c b/sound/soc/codecs/hda.c
>> index d2117e36ddd1..d9e7cd8aada2 100644
>> --- a/sound/soc/codecs/hda.c
>> +++ b/sound/soc/codecs/hda.c
>> @@ -350,6 +350,11 @@ static int hda_hdev_attach(struct hdac_device *hdev)
>>   	struct hda_codec *codec = dev_to_hda_codec(&hdev->dev);
>>   	struct snd_soc_component_driver *comp_drv;
>>   
>> +	if (hda_codec_is_display(codec) && !hdev->bus->audio_component) {
>> +		dev_dbg(&hdev->dev, "no i915, skip registration for 0x%08x\n", hdev->vendor_id);
>> +		return 0;
> 
> Should we return success here, or would it better with -ENODEV?
> IIUC, the code path is from the early hda_codec_driver_probe() hook,
> so returning an error can work.

Good suggestion. Indeed attach() is called by probe() which treats 
-ENODEV just fine.

There is a consequence to that though. Logs from LKF show:

snd_soc_hda_codec:hda_hdev_attach: snd_hda_codec_hdmi hdaudioB0D2: no 
i915, skip registration for 0x80862811
snd_soc_hda_codec:hda_hdev_attach: snd_hda_codec_generic hdaudioB0D2: no 
i915, skip registration for 0x80862811
snd_soc_hda_codec:hda_hdev_attach: snd_hda_codec_generic hdaudioB0D2: no 
i915, skip registration for 0x80862811
snd_hda_codec:snd_hda_codec_configure: hdaudio hdaudioB0D2: Unable to 
bind the codec
snd_soc_avs 0000:00:1f.3: failed to config codec -19
snd_soc_avs 0000:00:1f.3: Codec #2 probe error; disabling it...

i.e.: three attempts. One for HDMI via codec_bind_module() and two from 
codec_bind_generic(). Situation on CNL-based is different - two logs, no 
error. The reason for this is lack of codec->preset in LKF case.

Should I add stub entries for ICL-HP/LKF to patch_hdmi.c to address this?

HDA_CODEC_ENTRY(0x80862810, "Icelake-P HDMI",  NULL),
HDA_CODEC_ENTRY(0x80862811, "Lakefield HDMI",  NULL),


Czarek