From mboxrd@z Thu Jan 1 00:00:00 1970 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 8879B401484; Tue, 28 Apr 2026 10:42:23 +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=1777372943; cv=none; b=ERY6Gjtyvt2DQ5H4zKfONyYp9SCdUmnsEFej/w57peKFbGEDuYdSYzCq2ru4bmCw4rMfwh8JvniD5uPe12K59CxdTvQdn4ytACP7in3kXM2vAEbFVi/2NlINvmFR5a6SJ49WY3g1P8vGJ3+GcbLr6YVY7nApcrbllzivvcCsTvo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777372943; c=relaxed/simple; bh=gIV688uBFlsXlTT0uLql82n27evJwhecVjf4GCACkks=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=bupkD06cvU4yrBP5dG25/i5PeJhgqL4aDbBGQPi+ypyW7TUOGSaQTU77WY4ks/wq23wHOkUu+j9sYA7Ecg4S8M2f2yYfItIu5w4g4gH+Vp9cbxOoPPQKxA2Iw17dI8pBJfrSnYwACOfBrjjyOmSwXlH8ecwTHDWqt+bz4xGpDHk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=dVjXBWxH; 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="dVjXBWxH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2FFA5C2BCB8; Tue, 28 Apr 2026 10:42:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777372943; bh=gIV688uBFlsXlTT0uLql82n27evJwhecVjf4GCACkks=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dVjXBWxHm+zHlJoH/blcc+TrCd2An7ZaAYi1h09JpnS7E0Yc8yCmi0/iywi/Uh+d9 VkRhDi9Nfj0yJaKXpyYCW2LQbxDxof+gB8yhoABS7UpFh1IbRrC+4tn2zliy6IXu6A PR+ggk2oZhSIPjnFPwPF6xsh2TSrp1xWaRT6FWo2yfKbNeHfZTJNr/soaC6fny4PTm E4aYhfh7pBr/kLPGvBN0QLeyf/YX+ohQwu+HNvs9JhizeQipTXSORL2xGLFaXFbtqX v+n9z2Q1vxDxoKXq2eTTfeiXtUl79+D//nr8XH5l2HtFxgCY8xGNbriHgH0+u7ehqs Z1Uubzg5YDSKQ== From: Sasha Levin To: patches@lists.linux.dev, stable@vger.kernel.org Cc: Adrian Hunter , Bart Van Assche , "Martin K. Petersen" , Sasha Levin , jejb@linux.ibm.com, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH AUTOSEL 7.0-6.18] scsi: ufs: ufs-pci: Add support for Intel Nova Lake Date: Tue, 28 Apr 2026 06:40:46 -0400 Message-ID: <20260428104133.2858589-35-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260428104133.2858589-1-sashal@kernel.org> References: <20260428104133.2858589-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 7.0.2 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Adrian Hunter [ Upstream commit 096cd6b7adf21791827a045d464242d93a6fd54e ] Add PCI ID to support Intel Nova Lake, same as Intel Meteor Lake (MTL). Signed-off-by: Adrian Hunter Reviewed-by: Bart Van Assche Link: https://patch.msgid.link/20260309085815.55216-1-adrian.hunter@intel.com Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin --- LLM Generated explanations, may be completely bogus: Now I have enough information to complete the analysis. ## Phase 1: Commit Message Forensics **Step 1.1: Parse Subject Line** - Record: subsystem `scsi: ufs: ufs-pci:`, action verb `Add`, summary: "Add support for Intel Nova Lake" — hardware enablement via PCI ID **Step 1.2: Parse All Commit Message Tags** - Record: - Signed-off-by: Adrian Hunter (Intel, author, UFS PCI driver maintainer-level contributor) - Reviewed-by: Bart Van Assche (prolific SCSI/UFS reviewer) - Link: https://patch.msgid.link/20260309085815.55216-1- adrian.hunter@intel.com - Signed-off-by: Martin K. Petersen (SCSI subsystem maintainer) - No `Fixes:` tag, no `Cc: stable` (absence is expected per guidelines) - No `Reported-by:`, no syzbot **Step 1.3: Analyze Commit Body** - Record: The body is one sentence: "Add PCI ID to support Intel Nova Lake, same as Intel Meteor Lake (MTL)." Explicitly states the new platform reuses the existing MTL variant ops. No bug described — this is hardware enablement. **Step 1.4: Detect Hidden Bug Fixes** - Record: Not a hidden bug fix. This is a straightforward new-hardware- enablement PCI ID addition — which is an explicit exception category in the stable rules. ## Phase 2: Diff Analysis **Step 2.1: Inventory** - Record: 1 file changed (`drivers/ufs/host/ufshcd-pci.c`), +1/-0 lines. Scope: single-file, single-line surgical addition. Modified table: `ufshcd_pci_tbl[]`. **Step 2.2: Code Flow Change** - Record: Before: PCI device 0xD335 (INTEL) not matched → driver would not bind. After: PCI device 0xD335 matches and uses `ufs_intel_mtl_hba_vops`. Only affects the specific new device. **Step 2.3: Bug Mechanism** - Record: Category (h) Hardware workarounds — device ID addition. No bug mechanism; enables existing driver logic for a new SKU. **Step 2.4: Fix Quality** - Record: Trivially correct — simply matches the vendor/device pair to an existing, tested vops struct (`ufs_intel_mtl_hba_vops`). Zero regression risk: entries are only evaluated for matching vendor/device PCI IDs, so no non-Nova-Lake system can be affected. ## Phase 3: Git History Investigation **Step 3.1: Blame** - Record: The MTL vops struct `ufs_intel_mtl_hba_vops` was introduced by commit `4049f7acef3eb` ("scsi: ufs: ufs-pci: Add support for Intel MTL", Apr 2022, v5.18), which carried `Cc: stable@vger.kernel.org # v5.15+`. The MTL infrastructure is therefore in every active stable tree (5.15.y and later). **Step 3.2: Follow Fixes: Tag** - Record: No Fixes: tag — N/A. This is an enablement, not a fix. **Step 3.3: File History / Prerequisites** - Record: The surrounding PCI table has accumulated several similar single-line additions: Arrow Lake (`51031cc3f903e`, v6.5), Lunar Lake (`0a07d3c7a1d20`, v6.4), Panther Lake (`bdee2f1dcd84d`, v6.11), Wildcat Lake (`823f95575d854`, 2025). Each is identical in structure: one PCI ID reusing MTL ops. This commit is self-contained and has no prerequisites. **Step 3.4: Author's Other Commits** - Record: Adrian Hunter (Intel) is the long-time author/maintainer of the Intel UFS PCI support code. All past Intel PCI ID additions for this driver are his. Strong authority signal. **Step 3.5: Dependencies** - Record: The only dependency is `ufs_intel_mtl_hba_vops`, which has existed in stable since v5.15+. ## Phase 4: Mailing List Research **Step 4.1: Find Original Discussion** - Record: `b4 dig -c 096cd6b7adf21` matched by patch-id and returned htt ps://lore.kernel.org/all/20260309085815.55216-1- adrian.hunter@intel.com/ (only a single v1, no iterations). **Step 4.2: Reviewers** - Record: Bart Van Assche reviewed (Reviewed-by), Martin K. Petersen applied (SCSI maintainer). Addressed to linux-scsi@vger.kernel.org. Appropriate maintainer chain. **Step 4.3: Bug Report** - Record: No Reported-by/bug report — N/A (enablement). **Step 4.4: Related Patches** - Record: `b4 dig -a` confirmed only v1; no multi-patch series. Standalone. **Step 4.5: Stable-Specific Discussion** - Record: No explicit Cc: stable request in thread, but thread is clean and contains an Reviewed-by from Bart and a clean apply message from Martin. No objections. ## Phase 5: Code Semantic Analysis **Step 5.1: Functions Modified** - Record: No functions modified — only the PCI device ID table `ufshcd_pci_tbl[]`. **Step 5.2–5.4: Callers / Callees / Call Chain** - Record: The table is consumed by the PCI core (`pci_match_id`) for driver binding. Reachability: only when a Nova Lake host with PCI ID 8086:D335 is present. With no such device, the added row is dead data. **Step 5.5: Similar Patterns** - Record: Five identical prior commits add single MTL-compatible IDs (MTL itself, ARL, LNL, PTL, WCL). Consistent, well-established pattern. ## Phase 6: Cross-Referencing / Stable Tree Analysis **Step 6.1: Buggy Code in Stable?** - Record: The underlying driver + `ufs_intel_mtl_hba_vops` exist in all active stable trees (5.15.y and later, since v5.18 with Cc: stable # v5.15+). **Step 6.2: Backport Complications** - Record: Trivial clean apply expected — single-line addition to a table that exists in all active stable trees. Minor possibility of context fuzz if the table has slightly fewer entries in older branches (e.g., pre-Wildcat Lake), but still trivial. **Step 6.3: Related Fixes Already in Stable?** - Record: Panther Lake and Wildcat Lake PCI ID additions already made it to autosel stable branches (per `git branch --contains`), confirming the stable trees routinely accept this class of single-line Intel UFS PCI ID enablement. ## Phase 7: Subsystem Context **Step 7.1: Subsystem Criticality** - Record: `drivers/ufs/host/` — device driver for UFS (Universal Flash Storage). Criticality: IMPORTANT — UFS is the primary storage on modern Intel mobile/client platforms, so without this ID the system's main storage doesn't work at all on Nova Lake. **Step 7.2: Activity** - Record: Actively maintained; multiple commits per release. Mature, stable interfaces. ## Phase 8: Impact and Risk Assessment **Step 8.1: Affected Users** - Record: Users of Intel Nova Lake systems running a stable kernel. Without this patch, the UFS controller simply won't bind → the system cannot use its UFS storage. **Step 8.2: Trigger Conditions** - Record: Universally triggered on Nova Lake hardware at boot/probe. No special conditions. For all other hardware the code is inert. **Step 8.3: Failure Mode Severity** - Record: Without the patch: UFS storage inoperative on Nova Lake. With the patch: storage works. Severity for affected platform: HIGH (no storage = unusable system); for all other systems: zero impact. **Step 8.4: Benefit / Risk** - Record: BENEFIT: High for target hardware users, zero-cost for others. RISK: Essentially zero — only a PCI ID entry with a pointer to an existing, heavily-tested vops struct already in stable. Ratio strongly favors backport. ## Phase 9: Final Synthesis **Step 9.1: Evidence** - FOR: One-line PCI ID addition (exception category #1 in stable rules); reuses existing in-tree and in-stable `ufs_intel_mtl_hba_vops`; reviewed by Bart Van Assche; applied by Martin K. Petersen; obvious correctness; zero regression risk for non-matching hardware; matches the pattern of prior backported Intel UFS PCI ID additions (Arrow Lake, Lunar Lake, Panther Lake, Wildcat Lake). - AGAINST: None substantive. No explicit Cc: stable (but that's expected — would not be in review otherwise). **Step 9.2: Stable Rules Checklist** 1. Obviously correct and tested? YES — reviewed and applied by the maintainer; trivial addition. 2. Fixes a real problem for users? YES — UFS storage non-functional on Nova Lake without it. 3. Important? YES — primary storage on target platform. 4. Small & contained? YES — 1 line. 5. No new features/APIs? Correct — no user-visible API or new behavior; enables existing code path for a new device. 6. Applies to stable? YES — clean apply expected. **Step 9.3: Exception Category** - Record: Falls squarely under Exception Category #1 "NEW DEVICE IDs" — adding a PCI ID to an existing driver where the driver and the reused vops are already in stable. **Step 9.4: Decision** - YES. This is a textbook hardware enablement PCI ID addition that meets the explicit stable rule exception. --- ## Verification - [Phase 1] Parsed tags from commit message: Signed-off-by (Adrian Hunter, Martin K. Petersen), Reviewed-by (Bart Van Assche), Link to patch.msgid.link. No Fixes:, no Cc: stable, no Reported-by. - [Phase 2] `git show 096cd6b7adf21` confirmed: 1 file, +1/-0 line, single new entry `{ PCI_VDEVICE(INTEL, 0xD335), (kernel_ulong_t)&ufs_intel_mtl_hba_vops }` in `ufshcd_pci_tbl[]`. - [Phase 3] `git log -- drivers/ufs/host/ufshcd-pci.c` showed history of prior Intel PCI ID additions (MTL, ADL, ARL, LNL, PTL, WCL). - [Phase 3] `git show 4049f7acef3eb` confirmed the MTL support (introducing `ufs_intel_mtl_hba_vops`) carried `Cc: stable@vger.kernel.org # v5.15+`, so the vops exist in every active stable tree. - [Phase 3] `git branch --contains 823f95575d854` and `git branch --contains bdee2f1dcd84d` showed Wildcat Lake and Panther Lake PCI ID patches already in `for-greg/*-200` autosel branches — precedent for backporting this exact class of patch. - [Phase 3] Read `drivers/ufs/host/ufshcd-pci.c` lines 510–719: confirmed `ufs_intel_mtl_hba_vops` is defined at line 525 and already used by multiple MTL-family device IDs. - [Phase 4] `b4 dig -c 096cd6b7adf21`: matched by patch-id to https://lo re.kernel.org/all/20260309085815.55216-1-adrian.hunter@intel.com/. - [Phase 4] `b4 dig -c 096cd6b7adf21 -a`: confirmed only v1, no subsequent revisions. - [Phase 4] Mbox inspection: Martin K. Petersen applied ("Applied to 7.1/scsi-queue"), Bart Van Assche provided Reviewed-by. No NAKs, no objections. - [Phase 5] Inspection of `ufshcd_pci_tbl[]` surroundings: no functions modified, only table data; table is consumed by PCI core during driver binding. - [Phase 6] Confirmed `ufs_intel_mtl_hba_vops` is present in stable trees via the v5.15+ stable tag on commit 4049f7acef3eb. - [Phase 8] Failure mode analysis: without patch, Nova Lake UFS controller does not bind → no storage on that platform; with patch, it binds using the already-in-stable MTL vops. No risk to unrelated systems because the PCI core only dispatches to this driver on matching vendor:device. - UNVERIFIED: Did not fetch the lore.kernel.org thread via WebFetch (Anubis challenge page returned); mitigated by reading the thread contents directly from the b4-saved mbox (`/tmp/nova_lake_thread.mbox`), which contains the maintainer apply message and Bart's Reviewed-by. The commit is a minimal, low-risk, standards-compliant PCI device ID addition that enables UFS storage on a new Intel platform and reuses infrastructure already in all active stable trees. It fits the explicit "Adding PCI/USB/ACPI IDs to existing drivers" exception listed in the stable kernel rules, and matches the precedent of prior autosel-ed Intel UFS PCI ID additions (Panther Lake, Wildcat Lake). **YES** drivers/ufs/host/ufshcd-pci.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/ufs/host/ufshcd-pci.c b/drivers/ufs/host/ufshcd-pci.c index 5f65dfad1a71a..63f6b36b912fc 100644 --- a/drivers/ufs/host/ufshcd-pci.c +++ b/drivers/ufs/host/ufshcd-pci.c @@ -695,6 +695,7 @@ static const struct pci_device_id ufshcd_pci_tbl[] = { { PCI_VDEVICE(INTEL, 0x7747), (kernel_ulong_t)&ufs_intel_mtl_hba_vops }, { PCI_VDEVICE(INTEL, 0xE447), (kernel_ulong_t)&ufs_intel_mtl_hba_vops }, { PCI_VDEVICE(INTEL, 0x4D47), (kernel_ulong_t)&ufs_intel_mtl_hba_vops }, + { PCI_VDEVICE(INTEL, 0xD335), (kernel_ulong_t)&ufs_intel_mtl_hba_vops }, { } /* terminate list */ }; -- 2.53.0