[PATCH] ALSA: hda/realtek: Add quirk for LG gram 16 (16Z90SP)

["Prateek Yadav" <fyw21nur@rptu.de>]

The LG gram 16 (16Z90SP, SSID 1854:053b) drives its internal speakers
through Samsung-style smart amplifiers on an ALC298. Nothing
initialises them, so the internal speakers are silent after a cold
boot, while headphones, HDMI and the microphones work. A warm reboot
masks the problem, as the amps stay initialised.

Evidence (kernel 7.2.5-3-omarchy, sof-firmware 2025.12.2-1,
PipeWire 1.6.8):
- aplay -D plughw:0,0 completes with exit 0 but no audible output.
- During playback the codec shows Node 0x03 Converter stream=1,
   Amp-Out vals [0x69 0x69] unmuted, and Pin 0x17 OUT with EAPD on —
   the digital path is correct, the amps simply never start.
- Headphone Jack reports off, Speaker Phantom Jack reports on.
- Running the known 4-amp hda-verb init sequence
   (amps 0x38/0x39/0x3C/0x3D, cf. joshuagrisham/galaxy-book2-pro-linux
   necessary-verbs.sh) restores speaker output immediately.
- Machine dual-boots Windows, which explains cold-boot-only silence.

This mirrors the 16Z90TR (1854:0554) case fixed with
ALC298_FIXUP_SAMSUNG_AMP_V2_2_AMPS, and the 16" 16Z90R-A (1854:0489)
which uses the 4-amp variant. I verified the 4-amp init works on this
machine; please adjust to _2_AMPS if COEF 0x22 indicates two amps.

  sound/hda/codecs/realtek/alc269.c | 1 +
  1 file changed, 1 insertion(+)

diff --git a/sound/hda/codecs/realtek/alc269.c 
b/sound/hda/codecs/realtek/alc269.c
--- a/sound/hda/codecs/realtek/alc269.c
+++ b/sound/hda/codecs/realtek/alc269.c
@@ -8114,6 +8114,7 @@ static const struct hda_quirk alc269_fixup_tbl[] = {
      SND_PCI_QUIRK(0x1854, 0x0489, "LG gram 16 (16Z90R-A)", 
ALC298_FIXUP_SAMSUNG_AMP_V2_4_AMPS),
      SND_PCI_QUIRK(0x1854, 0x048a, "LG gram 17 (17ZD90R)", 
ALC298_FIXUP_SAMSUNG_AMP_V2_4_AMPS),
      SND_PCI_QUIRK(0x1854, 0x0490, "LG Gram Style 14 (14Z90RS)", 
ALC298_FIXUP_LG_GRAM_STYLE_14),
+    SND_PCI_QUIRK(0x1854, 0x053b, "LG gram 16 (16Z90SP)", 
ALC298_FIXUP_SAMSUNG_AMP_V2_4_AMPS),
      SND_PCI_QUIRK(0x1854, 0x0554, "LG gram 16 (16Z90TR)", 
ALC298_FIXUP_SAMSUNG_AMP_V2_2_AMPS),

Hardware: LG 16Z90SP-A.AD7BG, Intel Meteor Lake-P HD Audio [8086:7e28],
Realtek ALC298 [10ec:0298] rev 0x100103, SSID 1854:053b.
ALSA info: 
https://alsa-project.org/db/?f=7e8c49270f1b902ebb9fa76a4695f8301db040cf


Signed-off-by: Prateek prateek.yadav@edu.rptu.de