From nobody Mon Apr 6 09:09:43 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9E57C3D7D6E; Mon, 30 Mar 2026 12:39:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774874359; cv=none; b=S0Sf5r+v91WGaHIbnidtvnowGPS3q889eeTq3rzwgsrIh8pQQ+TDmogwPLmUDF7k90fUzvoYoCwba2a4hvvE41T583PqsxUulDtE3O6PB5bGjpngX+sHbiOBzkkpuqDclHgnW+KLRoJykSmMdeBlY6m+66Zv6Fdaui0W6UUE2p4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774874359; c=relaxed/simple; bh=dKuRGZG4/lteZTFXeqThLHmrHOH19quRHWpiId7Gqnk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=By3cCT+M2aSioH1yKUbo3XAk/jiX0gOtMiTkGr7udEJGAFAd+vAlW0yTjCRM7C++wRFvVP058Szgwwc1zSKTmQjceKKS1a/nz5EErLnpNa446bR4yMF5TT4d2hz4xlH1vY4l+XS33l2txnBazD8qyXwicd1Se8KED6Q5lqjkLDg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=IUlnilnb; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="IUlnilnb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7D634C4CEF7; Mon, 30 Mar 2026 12:39:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774874359; bh=dKuRGZG4/lteZTFXeqThLHmrHOH19quRHWpiId7Gqnk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IUlnilnbfiMymkgk47ZgCJRTKTLqkffjGbZYZ5SvvMlfyTvsrkv4T/J4ML65dy6B8 XNPpFeY1iizWCEoqofgvQbBY4Amk+nHnnmUl/b+ZRSRYnKGKoMk28VrXtEQbpKsneE R/BUaFMDP6+CT+62eJrcZH51OLvI+5w9vFrzH62/YuZLNoY2rZyzubuiKAR2AAZGDh umRlYcwMLbXlGqqIpRnF0eto7uzX6rp7qLzC9P8+BhaFRlmTyewdg8rmKJLf+sAlc2 PCMb6GCgasjgBeXvSieRqZBypV6biDP1FhRVBtSZibK/kNWvTfPFrAdKEnGgCaUrEJ 4+q80tCCYeTuw== From: Sasha Levin To: patches@lists.linux.dev, stable@vger.kernel.org Cc: Kshamendra Kumar Mishra , Takashi Iwai , Sasha Levin , perex@perex.cz, tiwai@suse.com, linux-sound@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH AUTOSEL 6.19-6.18] ALSA: hda/realtek: add HP Laptop 15-fd0xxx mute LED quirk Date: Mon, 30 Mar 2026 08:38:38 -0400 Message-ID: <20260330123842.756154-25-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260330123842.756154-1-sashal@kernel.org> References: <20260330123842.756154-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.19.10 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable From: Kshamendra Kumar Mishra [ Upstream commit faceb5cf5d7a08f4a40335d22d833bb75f05d99e ] HP Laptop 15-fd0xxx with ALC236 codec does not handle the toggling of the mute LED. This patch adds a quirk entry for subsystem ID 0x8dd7 using ALC236_FIXUP_HP_MUTE_LED_COEFBIT2 fixup, enabling correct mute LED behavior. Signed-off-by: Kshamendra Kumar Mishra Link: https://patch.msgid.link/DHAB51ISUM96.2K9SZIABIDEQ0@gmail.com Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin --- LLM Generated explanations, may be completely bogus: Now I have all the facts needed. Here is my comprehensive answer: --- ## Phase 1: Commit Message Forensics **Step 1.1: Parse the Subject Line** Record: [ALSA: hda/realtek] [add] [HP Laptop 15-fd0xxx mute LED quirk =E2= =80=94 adds SND_PCI_QUIRK entry for subsystem ID 0x103c:0x8dd7 using existing ALC236_FIXUP_HP_MUTE_LED_COEFBIT2 fixup] **Step 1.2: Parse All Commit Message Tags** Record: - `Signed-off-by: Kshamendra Kumar Mishra ` =E2=80=94 author - `Link: https://patch.msgid.link/DHAB51ISUM96.2K9SZIABIDEQ0@gmail.com` =E2=80=94 patch submission reference - `Signed-off-by: Takashi Iwai ` =E2=80=94 ALSA subsystem maintainer - No `Fixes:`, `Reported-by:`, `Tested-by:`, `Reviewed-by:`, `Acked- by:`, or `Cc: stable@vger.kernel.org` (expected for manual review candidates) **Step 1.3: Analyze the Commit Body Text** Record: Bug: HP Laptop 15-fd0xxx with ALC236 codec does not handle mute LED toggling. Symptom: Mute LED does not reflect mute state. Root cause: Missing SSID-to-fixup mapping in the quirk table. Fix: Add entry for subsystem ID 0x8dd7 pointing to existing `ALC236_FIXUP_HP_MUTE_LED_COEFBIT2`. **Step 1.4: Detect Hidden Bug Fixes** Record: Not a hidden bug fix =E2=80=94 this is an explicit hardware quirk addition. The message directly describes a non-working mute LED and the fixup that corrects it. ## Phase 2: Diff Analysis **Step 2.1: Inventory the Changes** Record: `sound/hda/codecs/realtek/alc269.c`: +1 line, -0 lines. Single `SND_PCI_QUIRK` entry added to `alc269_fixup_tbl[]` between existing entries 0x8dd4 and 0x8de8. Scope: single-file, single-line, table-data- only. **Step 2.2: Understand the Code Flow Change** Record: Before: No quirk entry for 0x103c:0x8dd7; `snd_hda_pick_fixup()` cannot select `ALC236_FIXUP_HP_MUTE_LED_COEFBIT2` for this machine, so the mute LED is not properly controlled. After: The SSID match triggers the existing fixup during codec probe, enabling correct mute LED behavior. **Step 2.3: Identify the Bug Mechanism** Record: Bug category: Hardware workaround / missing quirk entry. The `alc236_fixup_hp_mute_led_coefbit2()` helper programs `spec->mute_led_coef.idx =3D 0x07`, `mask =3D 1`, `on =3D 1`, `off =3D 0` a= nd registers `coef_mute_led_set` via `snd_hda_gen_add_mute_led_cdev()`. This is an existing, well-tested code path used by 17 other entries in this file. **Step 2.4: Assess the Fix Quality** Record: Obviously correct =E2=80=94 identical pattern to many existing HP A= LC236 quirk entries. Minimal and surgical. Regression risk is effectively zero since the new entry only matches one specific subsystem ID and uses an existing, well-exercised fixup chain. ## Phase 3: Git History Investigation **Step 3.1: Blame the Changed Lines** Record: The neighboring entries (0x8dd4 at line 7099, 0x8de8 at line 7100) confirm the correct insertion point. The new 0x8dd7 entry is not present in the current tree (verified by grep). **Step 3.2: Follow the Fixes Tag** Record: N/A =E2=80=94 no `Fixes:` tag present. **Step 3.3: Check File History for Related Changes** Record: Recent `alc269.c` history shows a steady stream of similar Realtek quirk additions (Acer, Samsung, HP models). This is a standalone one-line addition =E2=80=94 no patch series marker found. **Step 3.4: Check the Author's Other Commits** Record: The accepting maintainer is Takashi Iwai (`tiwai@suse.de`), the long-standing ALSA maintainer, providing strong endorsement of this quirk. **Step 3.5: Check for Dependent/Prerequisite Commits** Record: The prerequisite helper `ALC236_FIXUP_HP_MUTE_LED_COEFBIT2` was introduced by commit `0659400f18c0e6` ("ALSA: hda/realtek: Enable Mute LED on HP Laptop 15s-eq2xxx") which first appeared in `v6.5`. That commit itself had `Cc: stable@vger.kernel.org`. The helper exists in v6.5+, v6.6, and v6.19. It does **not** exist in v6.1 or v5.15. ## Phase 4: Mailing List and External Research **Step 4.1: Search Lore** Record: The `patch.msgid.link` URL returned an anti-bot page. Could not retrieve the actual patch discussion thread. UNVERIFIED: exact reviewer comments or stable nominations. **Step 4.2: Search for Bug Report** Record: No `Reported-by:` or bugzilla link. The only bug description is in the commit message itself. **Step 4.3: Check for Related Patches** Record: This is a standalone single-line quirk addition, not part of a multi-patch series. **Step 4.4: Check Stable Mailing List** Record: Similar HP Realtek mute LED quirks have been backported to stable before (e.g., the original `0659400f18c0e6` helper commit had `Cc: stable`). No specific stable discussion found for this exact patch. ## Phase 5: Code Semantic Analysis **Step 5.1: Key Functions** Record: No function body is modified. The change is data-only in `alc269_fixup_tbl[]`. The affected runtime function is the existing `alc236_fixup_hp_mute_led_coefbit2()`. **Step 5.2: Trace Callers** Record: `alc269_fixup_tbl[]` =E2=86=92 consumed by `snd_hda_pick_fixup()` c= alled from `alc269_probe()` =E2=86=92 registered as `.probe` in `alc269_codec_ops= ` / `alc269_driver` via `module_hda_codec_driver()`. The fixup runs at codec probe time on matching hardware. **Step 5.3: Trace Callees** Record: `alc236_fixup_hp_mute_led_coefbit2()` sets `spec->mute_led_coef` fields and calls `snd_hda_gen_add_mute_led_cdev(codec, coef_mute_led_set)`. `coef_mute_led_set()` calls `alc_update_coef_led()`. This only affects LED control, not audio routing or codec initialization logic. **Step 5.4: Call Chain Reachability** Record: HDA codec probe =E2=86=92 `alc269_probe()` =E2=86=92 `snd_hda_pick_= fixup(... alc269_fixup_tbl ...)` =E2=86=92 `snd_hda_apply_fixup(HDA_FIXUP_ACT_PRE_PRO= BE)` =E2=86=92 `alc236_fixup_hp_mute_led_coefbit2()`. Reachable only on systems = with the exact matching subsystem ID. **Step 5.5: Similar Patterns** Record: `ALC236_FIXUP_HP_MUTE_LED_COEFBIT2` appears 17 times in `alc269.c`, confirming it is a well-established fixup used by many HP devices. Related one-line commits include `d510acb610e6aa`, `d33c3471047fc`, `9ed7a28225af0`. ## Phase 6: Stable Tree Analysis **Step 6.1: Does the Buggy Code Exist in Stable Trees?** Record: The missing quirk (0x8dd7 absent) affects any stable tree that carries the `ALC236_FIXUP_HP_MUTE_LED_COEFBIT2` helper. Verified: - **v6.19**: helper present in `sound/hda/codecs/realtek/alc269.c` =E2=80= =94 **applicable** - **v6.6**: helper present in `sound/pci/hda/patch_realtek.c` (5 occurrences) =E2=80=94 **applicable** (minor path adjustment needed) - **v6.1**: helper **absent** (0 occurrences) =E2=80=94 **not standalone applicable** - **v5.15**: helper **absent** (0 occurrences) =E2=80=94 **not standalone applicable** **Step 6.2: Backport Complications** Record: For v6.19.y: clean apply expected (same file layout). For v6.6.y: needs minor mechanical adjustment (file is `sound/pci/hda/patch_realtek.c` instead of the new split path, and different surrounding context lines). For v6.1.y and v5.15.y: not a standalone backport =E2=80=94 prerequisite infrastructure absent. **Step 6.3: Related Fixes Already in Stable** Record: The original helper commit `0659400f18c0e6` had `Cc: stable@vger.kernel.org` and is present from v6.5 onward. The exact 0x8dd7 entry is not yet present anywhere (verified by grep). ## Phase 7: Subsystem and Maintainer Context **Step 7.1: Subsystem Criticality** Record: ALSA HDA Realtek codec driver =E2=80=94 IMPORTANT level for affected laptop users. Not core kernel, but real user-visible hardware functionality. **Step 7.2: Subsystem Activity** Record: Highly active =E2=80=94 frequent quirk additions and fixes to `alc269.c`, typical for ongoing hardware enablement. ## Phase 8: Impact and Risk Assessment **Step 8.1: Who Is Affected** Record: Users of HP Laptop 15-fd0xxx with ALC236 codec and subsystem ID 0x103c:0x8dd7. Driver-specific, hardware-specific. **Step 8.2: Trigger Conditions** Record: Every time the user mutes/unmutes audio, the LED does not correctly reflect the mute state. Affects normal daily use of the laptop. **Step 8.3: Failure Mode Severity** Record: Mute LED does not toggle =E2=80=94 user cannot visually confirm mute state. Severity: LOW-MEDIUM (hardware not working as designed, but no crash/corruption/security issue). **Step 8.4: Risk-Benefit Ratio** Record: Benefit: Restores expected mute LED behavior for a specific HP laptop model. Risk: Effectively zero =E2=80=94 one table entry matching a s= ingle subsystem ID, using an existing well-tested fixup chain. Ratio: Very favorable. ## Phase 9: Final Synthesis **Step 9.1: Compile the Evidence** Evidence FOR backporting: - Single-line hardware quirk addition =E2=80=94 explicit exception category= for stable - Uses existing, well-tested fixup (`ALC236_FIXUP_HP_MUTE_LED_COEFBIT2`, used by 17 other entries) - Zero regression risk (only matches one specific hardware subsystem ID) - Accepted by ALSA maintainer Takashi Iwai - Fixes real, user-visible hardware behavior for a shipping laptop model - The original helper commit had `Cc: stable@vger.kernel.org` =E2=80=94 the infrastructure was intended for stable Evidence AGAINST backporting: - Low severity (LED behavior only, not crash/security/corruption) - Not standalone for v6.1.y and v5.15.y (helper absent) Unresolved: - Exact mailing list review discussion (blocked by Anubis) - Independent testing beyond author and maintainer signoff **Step 9.2: Stable Rules Checklist** 1. Obviously correct and tested? **YES** =E2=80=94 identical pattern to 17 existing entries using the same fixup 2. Fixes a real bug? **YES** =E2=80=94 mute LED non-functional on specific hardware 3. Important issue? **MEDIUM** =E2=80=94 hardware not working as expected; = fits the quirk exception 4. Small and contained? **YES** =E2=80=94 1 line in 1 file 5. No new features or APIs? **YES** =E2=80=94 uses existing fixup 6. Can apply to stable? **YES** for v6.6.y and v6.19.y; **NO** as standalone for v6.1.y/v5.15.y **Step 9.3: Exception Category** Record: **Audio codec quirk** (`SND_PCI_QUIRK` entry for existing fixup) =E2=80=94 explicitly listed as an allowed exception for stable backporting. **Step 9.4: Decision** This is a textbook hardware quirk addition: one line, zero regression risk, existing infrastructure, maintainer-accepted. It should be backported to stable trees that already contain the `ALC236_FIXUP_HP_MUTE_LED_COEFBIT2` helper (v6.6.y and newer). ## Verification - [Phase 1] Parsed tags: `Signed-off-by` from author and ALSA maintainer Takashi Iwai; `Link:` to patch submission; no `Fixes:`, `Reported- by:`, or `Cc: stable` - [Phase 2] Diff analysis: +1 line `SND_PCI_QUIRK(0x103c, 0x8dd7, ...)` in `alc269_fixup_tbl[]`; verified 0x8dd7 not present in current tree (grep returned no matches) - [Phase 2] Read `alc236_fixup_hp_mute_led_coefbit2()` at lines 1525-1538: confirmed it sets `mute_led_coef.idx =3D 0x07`, `mask =3D 1`, `on =3D 1`, `off =3D 0` and calls `snd_hda_gen_add_mute_led_cdev()` - [Phase 2] Verified 17 occurrences of `ALC236_FIXUP_HP_MUTE_LED_COEFBIT2` in `alc269.c` =E2=80=94 well-establis= hed fixup - [Phase 3] `git log -S'ALC236_FIXUP_HP_MUTE_LED_COEFBIT2'` confirmed introduction by `0659400f18c0e6` and subsequent quirk additions - [Phase 3] `git show 0659400f18c0e6`: confirmed helper introduction with `Cc: ` - [Phase 3] `git tag --contains 0659400f18c0e6`: helper first appeared in v6.5 lineage - [Phase 3] Verified insertion point: 0x8dd4 at line 7099, 0x8de8 at line 7100 =E2=80=94 correct sorted position - [Phase 4] `patch.msgid.link` URL blocked by anti-bot protection =E2=80=94 UNVERIFIED: reviewer comments - [Phase 5] Traced call chain: `alc269_probe()` =E2=86=92 `snd_hda_pick_fix= up()` =E2=86=92 `snd_hda_apply_fixup()` =E2=86=92 helper. Probe-time only. - [Phase 6] **v6.6**: `ALC236_FIXUP_HP_MUTE_LED_COEFBIT2` present (5 occurrences in `patch_realtek.c`) =E2=80=94 applicable - [Phase 6] **v6.1**: helper absent (0 occurrences) =E2=80=94 NOT standalone applicable - [Phase 6] **v5.15**: helper absent (0 occurrences) =E2=80=94 NOT standalo= ne applicable - [Phase 8] Failure mode: non-functional mute LED only; severity LOW- MEDIUM; no crash/security/data path - UNVERIFIED: exact mailing list discussion content and any external test reports for this specific model **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/a= lc269.c index 5adc5db6fd52b..1054191d56fa1 100644 --- a/sound/hda/codecs/realtek/alc269.c +++ b/sound/hda/codecs/realtek/alc269.c @@ -7099,6 +7099,7 @@ static const struct hda_quirk alc269_fixup_tbl[] =3D { SND_PCI_QUIRK(0x103c, 0x8da7, "HP 14 Enstrom OmniBook X", ALC287_FIXUP_CS= 35L41_I2C_2), SND_PCI_QUIRK(0x103c, 0x8da8, "HP 16 Piston OmniBook X", ALC287_FIXUP_CS3= 5L41_I2C_2), SND_PCI_QUIRK(0x103c, 0x8dd4, "HP EliteStudio 8 AIO", ALC274_FIXUP_HP_AIO= _BIND_DACS), + SND_PCI_QUIRK(0x103c, 0x8dd7, "HP Laptop 15-fd0xxx", ALC236_FIXUP_HP_MUTE= _LED_COEFBIT2), SND_PCI_QUIRK(0x103c, 0x8de8, "HP Gemtree", ALC245_FIXUP_TAS2781_SPI_2), SND_PCI_QUIRK(0x103c, 0x8de9, "HP Gemtree", ALC245_FIXUP_TAS2781_SPI_2), SND_PCI_QUIRK(0x103c, 0x8dec, "HP EliteBook 640 G12", ALC236_FIXUP_HP_GPI= O_LED), --=20 2.53.0