On Sat, 25 Jul 2020 12:20:41 +0200, Yasushi SHOJI wrote:

Hi all,

I noticed that my 3 years old Lenovo X270 with Intel HDA & RealTek ALC298 doesn't work with 3.5 mm audio combo jack with 4 pole CTIA. A bit of googling showed me that `snd-hda-intel` module can take some options like `model` to run some fix ups. and I have found that `model=alc298-dell1` seems to at least work. But its gain is way too low. It's mostly just noise. It sounds like my mic is on the line-in.

So, I opened `patch_realtek.c` to see what's going on. I found the following but not sure what the values for `.v.pins` are for.

[ALC298_FIXUP_DELL1_MIC_NO_PRESENCE] = {
.type = HDA_FIXUP_PINS,
.v.pins = (const struct hda_pintbl[]) {
{ 0x18, 0x01a1913c }, /* use as headset mic, without its own jack detect */
{ 0x1a, 0x01a1913d }, /* use as headphone mic, without its own jack detect */
{ }
},
.chained = true,
.chain_id = ALC269_FIXUP_HEADSET_MODE
},

In `apply_fix(), these `.v.pins` values are passed to `snd_hda_apply_pincfgs()` but I can't find what values mean. Would someone please enlighten me?

My questions are

1. How can I found out which pin goes where. There is x270 schematics on the net but not sure it's correct.

It's often done by trial-and-error. Or sometimes the information can be extracted from Windows driver *.INI file. Or you can try hdajackretask program for figuring out those.

2. What does the value, ie, 0x01a1913d, represent?

At best take a look at HD-audio specification. You can find easily on the web.

Those are "pin configuration" values where various attributes like the jack type, the jack color, etc are embedded. The HD-audio driver looks through those configurations and determine the set up based on them.

HTH,

Takashi