[PATCH AUTOSEL 6.18-6.1] ALSA: hda/realtek: Add quirk for HP 255 15.6 inch G9 Notebook PC
From: Sasha Levin
Date: Mon Aug 31 2026 - 09:54:35 EST
From: Furst Blumier <seal@xxxxxxxxxx>
[ Upstream commit 98e157916f83c26a41448267180944048d2f1460 ]
The HP 255 15.6 inch G9 Notebook PC (PCI SSID 103c:8a1b) uses the
ALC236 codec but lacks an entry in the quirk table, causing the kernel
to fall back to a null SSID match (103c:0000) and skip the necessary
fixup. Add a quirk entry using ALC236_FIXUP_HP_MUTE_LED_COEFBIT2,
matching the HP 255 G8 which uses the same codec and fixup. This fixes
the mute-button LED and fixes an issue with unplugging and replugging a
headset jack not being recognized as an audio sink.
Signed-off-by: Furst Blumier <seal@xxxxxxxxxx>
Link: https://patch.msgid.link/20260609201706.502075-1-seal@xxxxxxxxxx
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
LLM Generated explanations, may be completely bogus:
# Stable Backport Analysis: ALSA HDA Realtek HP 255 G9 Quirk
**Local tree:** Linux **6.18.44** (`git describe HEAD` → `v6.18.44`,
Makefile `VERSION/PATCHLEVEL/SUBLEVEL` = 6/18/44)
---
## PHASE 1: COMMIT MESSAGE FORENSICS
### Step 1.1: Parse the subject line
**Record:** `[ALSA: hda/realtek]` `[Add]` — Add quirk for HP 255 15.6
inch G9 Notebook PC (PCI SSID quirk table entry).
### Step 1.2: Parse all commit message tags
**Record:**
- **Signed-off-by:** Furst Blumier `<seal@xxxxxxxxxx>` (author)
- **Link:**
https://patch.msgid.link/20260609201706.502075-1-seal@xxxxxxxxxx
- **Signed-off-by:** Takashi Iwai `<tiwai@xxxxxxx>` (ALSA/HDA
maintainer)
- No `Fixes:`, `Reported-by:`, `Tested-by:`, `Reviewed-by:`, `Cc:
stable@xxxxxxxxxxxxxxx`
- Notable: maintainer sign-off present; no syzbot/fuzzer report
### Step 1.3: Analyze commit body
**Record:**
- **Bug:** HP 255 15.6 inch G9 (PCI SSID `103c:8a1b`) uses ALC236 codec
but has no quirk entry.
- **Mechanism:** Kernel falls back to a generic/null SSID match
(`103c:0000`) and skips the needed fixup.
- **Symptoms:** Broken mute-button LED; unplugging/replugging a headset
jack is not recognized as an audio sink.
- **Fix approach:** Add quirk using `ALC236_FIXUP_HP_MUTE_LED_COEFBIT2`,
same as HP 255 G8.
- **Version info:** None stated in commit message.
### Step 1.4: Detect hidden bug fixes
**Record:** Not disguised — this is an explicit hardware quirk fix. It
is not a crash/security fix, but it fixes real, user-visible audio
behavior on a specific laptop model.
---
## PHASE 2: DIFF ANALYSIS
### Step 2.1: Inventory the changes
**Record:**
- **Files:** `sound/hda/codecs/realtek/alc269.c` (+1 line)
- **Functions modified:** None directly; change is in static
`alc269_fixup_tbl[]`
- **Scope:** Single-file, single-line surgical quirk addition
### Step 2.2: Code flow change
**Record:**
- **Before:** `103c:8a1b` has no entry in `alc269_fixup_tbl[]`; probe
falls through to a generic HP fixup (vendor table
`ALC269_FIXUP_HP_MUTE_LED` at line 7652) or no specific ALC236
coefbit2 fixup.
- **After:** Exact SSID match selects
`ALC236_FIXUP_HP_MUTE_LED_COEFBIT2` during `snd_hda_pick_fixup()` in
codec probe.
- **Path affected:** Codec initialization / probe path (boot and module
load).
### Step 2.3: Bug mechanism
**Record:**
- **Category:** Hardware workaround / audio codec quirk (HDA
pin/LED/jack configuration).
- **Mechanism:** Missing PCI SSID → wrong fixup applied → incorrect
mute-LED coefficient setup and headset jack behavior for ALC236 on
this board.
### Step 2.4: Fix quality assessment
**Record:**
- **Quality:** High — one-line addition, reuses an existing fixup
already applied to HP 255 G8 (`0x890e`) and HP 255 G10 (`0x8b2f`) in
this tree.
- **Regression risk:** Very low — no logic changes, no new APIs, no
structural changes.
---
## PHASE 3: GIT HISTORY INVESTIGATION
### Step 3.1: Blame the changed lines
**Record:** Insertion point is between lines 6843–6844 (after `0x8a0f`,
before `0x8a1f`). Neighbor entries added in commits like `bee43f7b9bc62`
(HP 14s-dr5xxx, `0x8a1f`) and `aeeb85f26c3bb` (Realtek driver split,
July 2025). The *absence* of `0x8a1b` is the bug — not a recently
introduced regression in existing code.
### Step 3.2: Follow Fixes: tag
**Record:** N/A — no `Fixes:` tag in commit message.
### Step 3.3: Related file history
**Record:** This tree regularly backports similar HDA Realtek quirk
commits (e.g. `bee43f7b9bc62` HP 14s-dr5xxx mute LED quirk,
`302eb87651326` HP Dragonfly Folio G3). Standalone one-liner; not part
of a multi-patch series.
### Step 3.4: Author's other commits
**Record:** No prior commits from Furst Blumier in
`sound/hda/codecs/realtek/` in this tree. Patch carries Takashi Iwai
maintainer sign-off.
### Step 3.5: Prerequisites / dependencies
**Record:**
- `ALC236_FIXUP_HP_MUTE_LED_COEFBIT2` enum, fixup table entry, and
`alc236_fixup_hp_mute_led_coefbit2()` all exist in this tree (lines
3875, 5552–5554, 1551–1563).
- HP 255 G8 (`0x890e`, line 6811) and HP 255 G10 (`0x8b2f`, line 6874)
already use the same fixup.
- **Can apply standalone:** Yes.
---
## PHASE 4: MAILING LIST AND EXTERNAL RESEARCH
### Step 4.1: Original patch discussion
**Record:** Could not retrieve — `b4 dig` requires a commit hash (not
provided); no matching mbox in workspace. `patch.msgid.link` and
`lore.kernel.org` blocked by Anubis bot protection.
### Step 4.2: Reviewers from b4 dig -w
**Record:** N/A — b4 dig not run (no commit hash available).
### Step 4.3: Bug report
**Record:** No external bug report linked beyond the patch submission
message-id. Author-reported hardware issue on HP 255 G9.
### Step 4.4: Related patches / series
**Record:** Same fixup pattern as HP 255 G8/G10 and multiple other HP
ALC236 laptops in `alc269_fixup_tbl[]`. Standalone patch.
### Step 4.5: Stable mailing list history
**Record:** UNVERIFIED — could not search lore stable list due to bot
protection.
---
## PHASE 5: CODE SEMANTIC ANALYSIS
### Step 5.1: Key functions
**Record:** Indirectly affects `alc269_probe()` → `snd_hda_pick_fixup()`
→ `alc236_fixup_hp_mute_led_coefbit2()` via fixup table selection.
### Step 5.2: Callers
**Record:** `snd_hda_pick_fixup()` called from `alc269.c` probe at lines
8471–8486 during HDA codec initialization (device probe at boot/module
load). Common path for all Realtek HDA laptops using this driver.
### Step 5.3: Callees
**Record:** Selected fixup `alc236_fixup_hp_mute_led_coefbit2()`
configures mute-LED coefficient registers (`spec->mute_led_coef.idx =
0x07`, etc.) and registers mute-LED cdev via
`snd_hda_gen_add_mute_led_cdev()`.
### Step 5.4: Call chain / reachability
**Record:** Triggered automatically at audio codec probe on affected
hardware — no userspace syscall needed. Every boot on HP 255 G9 without
this quirk gets wrong fixup.
### Step 5.5: Similar patterns
**Record:** At least 15 other machines in this tree use
`ALC236_FIXUP_HP_MUTE_LED_COEFBIT2`, including HP 255 G8 (`0x890e`) and
HP 255 G10 (`0x8b2f`). Same-generation G9 (`0x8a1b`) is the obvious
missing sibling.
---
## PHASE 6: CROSS-REFERENCING AGAINST LOCAL TREE
### Step 6.1: Does the buggy code exist?
**Record:** **Yes.** `0x8a1b` is absent from `alc269_fixup_tbl[]` in
v6.18.44. Confirmed by grep (no matches) and `git log -S "0x8a1b" --
sound/hda/` (empty). Adjacent entries `0x8a0f` and `0x8a1f` are present
at lines 6843–6844.
### Step 6.2: Backport complications
**Record:** **Clean apply expected** — single-line insertion in sorted
quirk table between existing HP entries. No structural divergence around
insertion point.
### Step 6.3: Related fixes already present?
**Record:** No prior fix for `103c:8a1b`. Related sibling quirks for HP
255 G8/G10 already present with same fixup type.
---
## PHASE 7: SUBSYSTEM AND MAINTAINER CONTEXT
### Step 7.1: Subsystem criticality
**Record:** `sound/hda/codecs/realtek` — **IMPORTANT** (laptop audio;
affects users of specific HP hardware, not universal).
### Step 7.2: Subsystem activity
**Record:** Actively maintained in 6.18.y — numerous recent Realtek
quirk backports in `git log --oneline -20 -- sound/hda/codecs/realtek/`.
---
## PHASE 8: IMPACT AND RISK ASSESSMENT
### Step 8.1: Who is affected
**Record:** Users of **HP 255 15.6 inch G9 Notebook PC** (PCI SSID
`103c:8a1b`) with ALC236 codec and `CONFIG_SND_HDA_CODEC_REALTEK`.
### Step 8.2: Trigger conditions
**Record:** Every boot / audio driver probe on affected hardware. Not
timing-dependent; deterministic. Unprivileged users cannot trigger the
fix, but all users of this laptop are affected without it.
### Step 8.3: Failure mode severity
**Record:**
- Mute LED does not work correctly
- Headset jack replug not recognized as audio sink
- **Severity: MEDIUM** — functional audio regression, not kernel crash,
data corruption, or security issue
### Step 8.4: Risk-benefit ratio
**Record:**
- **Benefit:** Restores correct audio jack detection and mute LED on a
real laptop model; matches established pattern for G8/G10 in same
product line.
- **Risk:** Minimal — one table entry, existing fixup, maintainer-
reviewed.
- **Ratio:** Favorable for stable backport under the hardware-quirk
exception.
---
## PHASE 9: FINAL SYNTHESIS
### Step 9.1: Evidence compile
**FOR backporting:**
- Fixes real hardware bug on HP 255 G9 (mute LED + headset jack)
- One-line, obviously correct quirk using proven existing fixup
- Same fixup as HP 255 G8 already in this tree
- ALC236 fixup infrastructure fully present in 6.18.44
- Takashi Iwai (maintainer) signed off
- Hardware quirk — explicit stable exception category
- This tree routinely takes similar HDA Realtek quirk patches
- Missing quirk confirmed in v6.18.44
**AGAINST backporting:**
- Not a crash, security, or data-corruption issue
- Affects only one specific laptop model
- No independent test report or syzbot validation
**UNRESOLVED:**
- Mailing list review thread content (blocked)
- Whether reviewers explicitly nominated for stable
### Step 9.2: Stable rules checklist
1. Obviously correct and tested? **PASS** — mirrors HP 255 G8;
maintainer SOB; standard quirk pattern.
2. Fixes a real bug affecting users? **PASS** — mute LED and headset
jack on real hardware.
3. Important issue? **PASS (borderline)** — not crash/security, but real
user-visible hardware malfunction; quirk exception applies.
4. Small and contained? **PASS** — 1 line, 1 file.
5. No new features or APIs? **PASS** — table entry only, reuses existing
fixup.
6. Can apply to local tree? **PASS** — prerequisites present; clean
insertion.
### Step 9.3: Exception category
**Record:** **Hardware quirk/workaround** — adding PCI SSID entry to
existing Realtek HDA driver quirk table. This is one of the explicitly
allowed stable exceptions.
### Step 9.4: Decision rationale
For Linux **6.18.44**, owners of the HP 255 15.6 inch G9 hit wrong HDA
fixup behavior because `103c:8a1b` is missing from the quirk table while
the needed `ALC236_FIXUP_HP_MUTE_LED_COEFBIT2` fixup and sibling entries
(HP 255 G8/G10) are already present. The patch is a minimal, maintainer-
approved hardware quirk of the kind routinely accepted into stable
trees. Severity is functional rather than catastrophic, but the stable-
kernel rules explicitly welcome such quirks, and the risk of regression
is negligible.
---
## Verification
- **[Phase 1]** Parsed subject, tags, and body from provided commit
message.
- **[Phase 1]** Confirmed Takashi Iwai maintainer sign-off; no
syzbot/Fixes: tags.
- **[Phase 2]** Diff: +1 line `SND_PCI_QUIRK(0x103c, 0x8a1b, ...)` in
`alc269_fixup_tbl[]`.
- **[Phase 2]** Read `alc236_fixup_hp_mute_led_coefbit2()` at lines
1551–1563.
- **[Phase 3]** `git blame -L 6840,6846`: neighbors from commits
`302eb87651326`, `bee43f7b9bc62`, `aeeb85f26c3bb`.
- **[Phase 3]** `git log -S "ALC236_FIXUP_HP_MUTE_LED_COEFBIT2"`: fixup
present since driver split and earlier quirk commits.
- **[Phase 3]** `git log -S "0x8a1b" -- sound/hda/`: empty — quirk never
added to this tree.
- **[Phase 4]** UNVERIFIED: `b4 dig` not run (no commit hash provided).
- **[Phase 4]** UNVERIFIED: lore.kernel.org and patch.msgid.link blocked
by Anubis.
- **[Phase 5]** Read `snd_hda_pick_fixup()` in
`sound/hda/common/auto_parser.c` lines 1006–1103.
- **[Phase 5]** Read probe call sites at `alc269.c` lines 8471–8486.
- **[Phase 5]** Grep: `ALC236_FIXUP_HP_MUTE_LED_COEFBIT2` used by HP 255
G8 (`0x890e`, line 6811) and G10 (`0x8b2f`, line 6874).
- **[Phase 6]** `git describe HEAD` → `v6.18.44`; Makefile confirms
6.18.44.
- **[Phase 6]** Grep for `0x8a1b` / `HP 255 15.6 inch G9`: no matches in
tree.
- **[Phase 6]** Read insertion area lines 6840–6846: gap between
`0x8a0f` and `0x8a1f` confirmed.
- **[Phase 7]** `git log --oneline -20 -- sound/hda/codecs/realtek/`:
active quirk backport activity.
- **[Phase 8]** Failure mode assessed as functional audio (MEDIUM), not
crash/security.
**YES**
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
index 0c23eb601ecaa..0ef5468b0701a 100644
--- a/sound/hda/codecs/realtek/alc269.c
+++ b/sound/hda/codecs/realtek/alc269.c
@@ -6841,6 +6841,7 @@ static const struct hda_quirk alc269_fixup_tbl[] = {
SND_PCI_QUIRK(0x103c, 0x89e7, "HP Elite x2 G9", ALC245_FIXUP_CS35L41_SPI_2_HP_GPIO_LED),
SND_PCI_QUIRK(0x103c, 0x8a06, "HP Dragonfly Folio G3 2-in-1", ALC245_FIXUP_CS35L41_SPI_4_HP_GPIO_LED),
SND_PCI_QUIRK(0x103c, 0x8a0f, "HP Pavilion 14-ec1xxx", ALC287_FIXUP_HP_GPIO_LED),
+ SND_PCI_QUIRK(0x103c, 0x8a1b, "HP 255 15.6 inch G9 Notebook PC", ALC236_FIXUP_HP_MUTE_LED_COEFBIT2),
SND_PCI_QUIRK(0x103c, 0x8a1f, "HP Laptop 14s-dr5xxx", ALC236_FIXUP_HP_MUTE_LED_COEFBIT2),
SND_PCI_QUIRK(0x103c, 0x8a20, "HP Laptop 15s-fq5xxx", ALC236_FIXUP_HP_MUTE_LED_COEFBIT2),
SND_PCI_QUIRK(0x103c, 0x8a25, "HP Victus 16-d1xxx (MB 8A25)", ALC245_FIXUP_HP_MUTE_LED_COEFBIT),
--
2.53.0