[Bug 222044] hp-wmi: Mute and mic-mute LEDs not supported on HP Laptop 15-fc0xxx (board 8DC9)

[bugzilla-daemon@kernel.org]

https://bugzilla.kernel.org/show_bug.cgi?id=222044

--- Comment #5 from Piyush (aryanbabupiyushbabu@gmail.com) ---
Update on kernel fixup implementation and testing:

I built and tested a custom patch against sound/hda/codecs/realtek/alc269.c
incorporating both identified controls.

======================================================================
1. CODE IMPLEMENTATION
======================================================================

Added fixup function:
---------------------
static void alc236_fixup_hp_15_fc0xxx_led(struct hda_codec *codec,
                                         const struct hda_fixup *fix, int
action)
{
        struct alc_spec *spec = codec->spec;

        if (action == HDA_FIXUP_ACT_PRE_PROBE) {
                /* F5 Speaker Mute LED: Node 0x20, COEF 0x07, Bit 0 */
                spec->mute_led_polarity = 0;
                spec->mute_led_coef.idx = 0x07;
                spec->mute_led_coef.mask = 0x01;
                spec->mute_led_coef.on = 0x01;
                spec->mute_led_coef.off = 0x00;
                snd_hda_gen_add_mute_led_cdev(codec, coef_mute_led_set);

                /* F8 Mic Mute LED: Node 0x01, GPIO 0, Active-Low */
                spec->micmute_led_polarity = 1;
        }

        /* Wire GPIO 0 for mic mute LED */
        alc_fixup_hp_gpio_led(codec, action, 0x00, 0x01);
}

Fixup table chaining and quirk:
-------------------------------
[ALC236_FIXUP_HP_DMIC] = {
        .type = HDA_FIXUP_PINS,
        .v.pins = (const struct hda_pintbl[]) {
                { 0x12, 0x90a60160 }, /* use as internal mic */
                { }
        },
        .chained = true,
        .chain_id = ALC236_FIXUP_HP_MUTE_LED,
},
[ALC236_FIXUP_HP_MUTE_LED] = {
        .type = HDA_FIXUP_FUNC,
        .v.func = alc236_fixup_hp_15_fc0xxx_led,
},

/* Quirk table entry */
SND_PCI_QUIRK(0x103c, 0x8dc9, "HP Laptop 15-fc0xxx", ALC236_FIXUP_HP_DMIC),


======================================================================
2. HARDWARE VERIFICATION
======================================================================

- Speaker Mute LED (F5):
  Works as expected across environments, synchronizing with master playback
mute.

- Mic Mute LED (F8):
  Hardware wiring is verified working via ALSA:
    amixer -c 1 sset Capture toggle
  Directly toggling this switch flips /sys/class/leds/hda::micmute/brightness 
  between 0 and 1, and the physical amber LED turns on and off accordingly.


======================================================================
3. PARTITION & USERSPACE TESTING OBSERVATIONS
======================================================================

I tested this exact kernel build across two different partitions:

- Partition 1:
  Worked as intended out of the box, with the LED tracking mic state cleanly.

- Partition 2 (Primary, running KDE Plasma / PipeWire with ALSA UCM HiFi
profile):
  An unexpected quirk appeared:
  * The machine requires the internal digital microphone fixup at pin 0x12
(ALC236_FIXUP_HP_DMIC: 0x90a60160).
  * ALSA registers both the legacy analog Capture switch (numid=7) and the DMIC
endpoint. On this setup, the analog 'Capture Switch' (numid=7) initialized to
[off] (muted).
  * KDE / WirePlumber manages and mutes the DMIC stream
(alsa_input.*.HiFi__Mic1__source) without touching numid=7.
  * Because the kernel's generic audio-micmute trigger in hda_generic.c
monitors all registered capture switches and sees numid=7 permanently muted,
the F8 LED remained locked ON (brightness 1) at startup regardless of software
mute toggles.


======================================================================
4. FEEDBACK REQUEST
======================================================================

Could you advise on the preferred upstream approach to structure or chain the
micmute LED fixup when ALC236_FIXUP_HP_DMIC is active so the LED remains
synchronized with the DMIC stream state regardless of userspace mixer defaults?

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