sof-essx8336: Internal mic only picks up noise unless headphone jack is physically inserted (OEM board with empty DMI strings)

[Goldicode]

Summary

On my laptop (cheap whitelabel/OEM device, sold under the brand "Denver"),
the internal microphone (ES8336 codec, sof-essx8336 machine driver) only
records noise. As soon as any plug is inserted into the headphone jack
(even without audio playing), the internal microphone works correctly.
This suggests a jack-detection / GPIO polarity issue rather than a mixer
or clock problem.

On the same hardware, the microphone works correctly under Windows at
all times, regardless of whether headphones are plugged in.

Hardware

• Board: whitelabel/OEM ("Denver" branded), DMI strings not populated
  by OEM (baseboard-product-name / system-product-name report "Default
  string" via dmidecode)
• Codec: ES8336 (sof-essx8336)
• Platform: Intel Gemini Lake (Apollo Lake DSP class, topology
  sof-glk-es8336-ssp2.tplg)

Kernel / Software

• Kernel: 7.1.8-1-cachyos
• Distro: CachyOS (Arch-based)
• SOF firmware: version 2:2:0-57864, ABI 3:22:1
• Current quirk mask: 0x2 (SSP2 only — no board-specific quirk applied,
  presumably because DMI strings are not populated on this OEM board)

ACPI GPIO info (from DSDT, ESSX8336 device)

Method (_CRS, 0, NotSerialized)
{
I2cSerialBusV2 (0x0011, ControllerInitiated, 0x00061A80,
AddressingMode7Bit, "_SB.PCI0.I2C2", ...)
GpioIo (Exclusive, PullDefault, 0x0000, 0x0000, IoRestrictionOutputOnly,
"_SB.GPO1", 0x00, ResourceConsumer, ,)
{ 0x001D } // GPIO 29, output
GpioInt (Edge, ActiveHigh, ExclusiveAndWake, PullDefault, 0x0000,
"_SB.GPO1", 0x00, ResourceConsumer, ,)
{ 0x0014 } // GPIO 20, interrupt (jack detect?)
}

dmesg (relevant excerpt)

[ 11.462771] sof-audio-pci-intel-apl 0000:00:0e.0: DSP detected with PCI class/subclass/prog-if 0x040100
[ 11.509085] sof-audio-pci-intel-apl 0000:00:0e.0: NHLT device BT(0) detected, ssp_mask 0x4
[ 11.509093] sof-audio-pci-intel-apl 0000:00:0e.0: DMICs detected in NHLT tables: 0
[ 11.509095] sof-audio-pci-intel-apl 0000:00:0e.0: NHLT device I2S(4) detected, ssp_mask 0x5
[ 11.517350] sof-audio-pci-intel-apl 0000:00:0e.0: Topology file: intel/sof-tplg/sof-glk-es8336-ssp2.tplg
[ 11.592718] sof-essx8336 sof-essx8336: quirk mask 0x2
[ 11.592726] sof-essx8336 sof-essx8336: quirk SSP2
[ 11.600658] es8316 i2c-ESSX8336:00: assuming static mclk

Steps to reproduce

1. Boot Linux, do not connect anything to the headphone jack.
2. Record from the internal mic (arecord -D hw:0,0 -f S16_LE -r 48000 -c 2 -d 5 test.wav).
3. Play back — only noise, no voice signal, regardless of
   'Differential Mux' setting (lin1-rin1 / lin2-rin2, with or
   without 20dB boost) or 'Mic Boost' setting.
4. Insert any 3.5mm plug into the headphone jack (no audio playback
   needed) and repeat step 2/3 — microphone now works correctly.

Expected behavior

Internal microphone should work correctly regardless of headphone
jack state, as it does on the same hardware under Windows.

Additional notes

• DMI strings on this board are unpopulated ("Default string"),
  which likely prevents any existing sof_es8336_quirk_table DMI
  match (similar to the existing Huawei Matebook D15 quirk) from
  applying.
• Manually testing quirk=64 (attempted JD_INVERTED bit) via
  modprobe.d caused topology loading to fail entirely
  (tplg ... component load failed -22), breaking all audio
  output and input — reverted.
• Happy to test further quirk values or provide additional debug
  output (alsa-info, sof-logger) if a maintainer can suggest safe
  values to try, given the DSDT GPIO info above.