From: David Heidelberg <[email protected]> [ Upstream commit ae3aa8cf5fd5ccb428a814e7eb38ae33ad1cfa34 ]
These panels used on sdm845 devices are using GPIOLIB functions, ensure it's enabled. Signed-off-by: David Heidelberg <[email protected]> Reviewed-by: Neil Armstrong <[email protected]> Signed-off-by: Neil Armstrong <[email protected]> Link: https://patch.msgid.link/[email protected] Signed-off-by: Sasha Levin <[email protected]> --- LLM Generated explanations, may be completely bogus: # Stable Backport Analysis: `drm/panel: Enable GPIOLIB for panels which uses functions from it` **Local tree:** Linux **6.18.43** (`git describe HEAD` → `v6.18.43-1-gc7f0dac02d232`) --- ## PHASE 1: COMMIT MESSAGE FORENSICS ### Step 1.1: Parse the subject line **Record:** `[drm/panel]` `[Enable]` — Add missing `GPIOLIB` Kconfig dependencies for DRM panel drivers that call GPIO descriptor APIs. ### Step 1.2: Parse all commit message tags **Record:** - **Signed-off-by:** David Heidelberg `<[email protected]>` (author) - **Reviewed-by:** Neil Armstrong `<[email protected]>` (drm/panel maintainer) - **Signed-off-by:** Neil Armstrong `<[email protected]>` - **Link:** https://patch.msgid.link/20260505-panel-clean-up-kconfig- [email protected] - No `Fixes:`, `Reported-by:`, `Cc: [email protected]`, or syzbot tags - Notable: Reviewed-by from subsystem maintainer; patch 4/4 of a Kconfig cleanup series (v2) ### Step 1.3: Analyze commit body **Record:** - **Bug:** Five panel Kconfig entries can be enabled without `GPIOLIB`, even though their `.c` drivers call `devm_gpiod_get()` / `gpiod_set_value*()`. - **Symptom:** Broken or invalid kernel configuration on SDM845-class devices (Poco F1, etc.); panel drivers selected without GPIO support compiled in. - **Root cause:** Missing `depends on GPIOLIB` in Kconfig for drivers that use GPIO consumer APIs. - **Version info:** None in commit message. ### Step 1.4: Detect hidden bug fixes **Record:** Yes — presented as Kconfig cleanup, but it fixes a real configuration correctness bug. Without `GPIOLIB`, `devm_gpiod_get()` stubs return `-ENOSYS` and probe fails (verified in `panel-ebbg- ft8719.c`). Not a crash, but a broken driver configuration path. --- ## PHASE 2: DIFF ANALYSIS ### Step 2.1: Inventory the changes **Record:** - **Files:** `drivers/gpu/drm/panel/Kconfig` only (+9 / -2) - **Configs modified:** 7 entries - **Adds `depends on GPIOLIB`:** `DRM_PANEL_EBBG_FT8719`, `DRM_PANEL_LG_SW43408`, `DRM_PANEL_NOVATEK_NT36672A`, `DRM_PANEL_NOVATEK_NT36672E`, `DRM_PANEL_VISIONOX_RM69299` - **Reformats only (already had GPIOLIB):** `DRM_PANEL_JDI_LPM102A188A`, `DRM_PANEL_RAYDIUM_RM69380` (`depends on OF && GPIOLIB` → separate lines) - **Scope:** Single-file, surgical Kconfig fix ### Step 2.2: Code flow change **Record:** - **Before:** Kconfig allows `CONFIG_DRM_PANEL_*=y/m` with `CONFIG_GPIOLIB=n`. - **After:** Panel options are only visible/selectable when `GPIOLIB` is enabled, ensuring GPIO infrastructure is present when these drivers are built. - **Affected path:** Kernel configuration / module build selection, not runtime hot path. ### Step 2.3: Bug mechanism **Record:** - **Category:** Kconfig dependency / configuration correctness (related to build-fix exception) - **Mechanism:** Drivers include `<linux/gpio/consumer.h>` and call `devm_gpiod_get()` / `gpiod_set_value*()`. Without `depends on GPIOLIB`, Kconfig does not enforce the dependency. With `GPIOLIB=n`, header stubs compile but return `-ENOSYS` at probe time. ### Step 2.4: Fix quality **Record:** Obviously correct and minimal. Each affected driver verified to use GPIO APIs. No runtime logic changed. Regression risk: very low (Kconfig-only). Two entries already had GPIOLIB — only formatting changes there. --- ## PHASE 3: GIT HISTORY INVESTIGATION ### Step 3.1: Blame changed lines **Record:** Affected Kconfig entries trace to `19eef1d98eeda` in this tree's history. Drivers have used `devm_gpiod_get` since introduction (verified via `git log -S devm_gpiod_get`). Bug present since drivers were added without GPIOLIB dependency. ### Step 3.2: Follow Fixes: tag **Record:** N/A — no `Fixes:` tag. ### Step 3.3: File history for related changes **Record:** Recent `Kconfig` changes in this tree: - `3139b806923b1` — `drm/panel: s6e3ha8: fix unmet dependency on DRM_DISPLAY_HELPER` (already backported) - `d003d9bb44da1` — `drm/panel: Clean up S6E3HA2 config dependencies` — **patch 3/4 of same series**, adds GPIOLIB to S6E3HA8 (already backported) - This commit (patch 4/4) is **not** in HEAD (`ae3aa8cf5fd5` is not an ancestor of HEAD) ### Step 3.4: Author's other commits **Record:** David Heidelberg authored `d003d9bb44da1` (patch 3, already in 6.18.y). Neil Armstrong reviewed both. ### Step 3.5: Prerequisites **Record:** Standalone Kconfig change. Patch 3 of the series is already in this tree; patch 1 (S6E3FC2X01) is not present (that config doesn't exist here). This patch applies independently for the five panels missing GPIOLIB. --- ## PHASE 4: MAILING LIST AND EXTERNAL RESEARCH ### Step 4.1: Original patch discussion **Record:** `b4 dig -c ae3aa8cf5fd5 -a` found v1 and v2 series on lore. v2 message ID matches commit Link tag. `b4 dig -w` failed (lore fetch error). WebFetch of lore blocked by Anubis bot protection. Web search confirmed upstream commit `ae3aa8cf5fd5` and series context. ### Step 4.2: Reviewers **Record:** Neil Armstrong (drm/panel maintainer) provided `Reviewed- by`. Series cover letter (from search) describes Kconfig dependency cleanup verified against all driver source files. ### Step 4.3: Bug report **Record:** No formal bug report or syzbot link. Issue identified through Kconfig dependency audit (same class as `kconfirm`-found s6e3ha8 fix already in this tree). ### Step 4.4: Related patches **Record:** 4-patch series: 1. S6E3FC2X01 cleanup — not applicable (config absent in 6.18.y) 2. (unclear numbering in resends) 3. S6E3HA2 GPIOLIB + help text — **already in tree** (`d003d9bb44da1`) 4. **This commit** — GPIOLIB for 5 additional panels ### Step 4.5: Stable mailing list **Record:** UNVERIFIED — lore stable search blocked. No evidence against backport found. --- ## PHASE 5: CODE SEMANTIC ANALYSIS ### Step 5.1: Key functions **Record:** No C functions modified. Affected probe functions in driver `.c` files use GPIO APIs: - `panel_ebbg_ft8719_probe()` — `devm_gpiod_get()`, `gpiod_set_value_cansleep()` - `panel_lg_sw43408` — `devm_gpiod_get()`, `gpiod_set_value()` - `panel_novatek_nt36672a/e` — `devm_gpiod_get()`, `gpiod_set_value()` - `panel_visionox_rm69299` — `devm_gpiod_get()`, `gpiod_set_value()` ### Step 5.2: Callers **Record:** Probe functions called from module init / device registration during boot on platforms with these panels (SDM845 phones, Poco F1, etc.). ### Step 5.3: Callees **Record:** `devm_gpiod_get()`, `gpiod_set_value()`, `gpiod_set_value_cansleep()` from GPIOLIB (or stubs when `GPIOLIB=n`). ### Step 5.4: Reachability **Record:** Reachable on ARM64 platforms with these panel device trees when the panel driver is enabled. Common on SDM845 devices mentioned in the commit message. ### Step 5.5: Similar patterns **Record:** Many other panel Kconfig entries in the same file already have `depends on GPIOLIB`. S6E3HA8 received the same fix in `d003d9bb44da1` already backported here. Consistent with established pattern. --- ## PHASE 6: CROSS-REFERENCING AGAINST LOCAL TREE ### Step 6.1: Does buggy code exist? **Record:** **Yes.** In 6.18.43, these five configs lack `GPIOLIB`: - `DRM_PANEL_EBBG_FT8719` (line 110: `depends on OF` only) - `DRM_PANEL_LG_SW43408` (line 421) - `DRM_PANEL_NOVATEK_NT36672A` (line 525) - `DRM_PANEL_NOVATEK_NT36672E` (line 535) - `DRM_PANEL_VISIONOX_RM69299` (line 1121) All five driver `.c` files confirmed to use GPIO APIs. ### Step 6.2: Backport complications **Record:** Clean apply expected — single Kconfig file, no conflicts with recent changes. Two configs (`JDI_LPM102A188A`, `RAYDIUM_RM69380`) already have GPIOLIB; only formatting differs. ### Step 6.3: Related fixes already present? **Record:** Patch 3 of same series (`d003d9bb44da1`) and similar unmet- dependency fix (`3139b806923b1`) already backported. **This specific fix is not yet in the tree.** --- ## PHASE 7: SUBSYSTEM AND MAINTAINER CONTEXT ### Step 7.1: Subsystem criticality **Record:** `drivers/gpu/drm/panel` — **IMPORTANT** (display subsystem, mobile/embedded hardware). ### Step 7.2: Subsystem activity **Record:** Active — recent Kconfig dependency fixes backported to this 6.18.y tree in the same subsystem. --- ## PHASE 8: IMPACT AND RISK ASSESSMENT ### Step 8.1: Who is affected **Record:** Users of SDM845-class mobile devices (Poco F1, etc.) and anyone building custom kernels with these panel drivers. Config- specific, not universal. ### Step 8.2: Trigger conditions **Record:** Triggered when `CONFIG_DRM_PANEL_<name>=y/m` with `CONFIG_GPIOLIB=n`. Uncommon on ARM mobile defconfigs (GPIOLIB typically enabled), but possible with custom/randconfig builds. Not a security issue. ### Step 8.3: Failure mode severity **Record:** Panel probe fails with `-ENOSYS` from `devm_gpiod_get()` stub; display non-functional. **Severity: MEDIUM** (broken hardware support, not crash/corruption). Kconfig tools may also report unmet dependencies. ### Step 8.4: Risk-benefit **Record:** - **Benefit:** MEDIUM — correct Kconfig dependencies; prevents broken panel configs; completes a series partially already backported - **Risk:** VERY LOW — Kconfig-only, 9 lines, maintainer-reviewed - **Ratio:** Favorable for backport, especially given precedent in this tree --- ## PHASE 9: FINAL SYNTHESIS ### Step 9.1: Evidence compile **FOR backport:** - Real Kconfig bug: 5 drivers use GPIOLIB APIs without declaring dependency - Verified in source for all 5 drivers - Small, surgical, maintainer-reviewed (Neil Armstrong) - Patch 3 of same series already backported to 6.18.y - Similar Kconfig unmet-dependency fix (`3139b806923b1`) already in this tree - Build/config fix exception category - Affects real mobile hardware (SDM845 panels) - Zero runtime regression risk **AGAINST backport:** - Does not cause compile failure (`gpio/consumer.h` provides stubs when `GPIOLIB=n`) - Runtime failure is graceful probe error, not crash/UAF/corruption - Typical ARM mobile defconfigs already enable GPIOLIB - Low practical impact for most production users **Unresolved:** - Full lore review thread (Anubis blocked WebFetch) - Whether randconfig/kconfirm explicitly flagged these five panels ### Step 9.2: Stable rules checklist 1. Obviously correct and tested? **PASS** — verified driver/GPIO usage; Reviewed-by from maintainer 2. Fixes a real bug? **PASS** — Kconfig allows invalid configuration for real hardware 3. Important issue? **PASS (MEDIUM)** — broken display driver config, not crash/security 4. Small and contained? **PASS** — 1 file, +9/-2 lines 5. No new features/APIs? **PASS** — Kconfig dependency only 6. Can apply to local tree? **PASS** — buggy code present; clean apply expected ### Step 9.3: Exception categories **Record:** **Build/config fix** — Kconfig dependency correction (same class as `3139b806923b1` and `d003d9bb44da1` already in 6.18.y). ### Step 9.4: Decision rationale This is not a critical crash fix, but it is a correct, zero-risk Kconfig dependency fix for real hardware panel drivers. The 6.18.y tree has already accepted two nearly identical drm/panel Kconfig dependency fixes from the same author and reviewer, including patch 3 of this very series. Leaving patch 4 out leaves five panel drivers with the same class of bug that was already fixed for S6E3HA8. The fix is small, obviously correct, and completes consistent Kconfig hygiene in a subsystem where this tree has established precedent. --- ## Verification - [Phase 1] Parsed subject, tags; found Reviewed-by Neil Armstrong, Link to v2-4 patch - [Phase 2] Diff: 1 file, +9/-2; 5 configs gain GPIOLIB, 2 reformat only - [Phase 2] Verified `panel-ebbg-ft8719.c` uses `devm_gpiod_get` + `gpiod_set_value_cansleep` - [Phase 2] Verified `panel-lg-sw43408.c`, `panel-novatek-nt36672a.c`, `panel-novatek-nt36672e.c`, `panel-visionox-rm69299.c` use GPIO APIs - [Phase 2] Read `include/linux/gpio/consumer.h`: stubs provided when `CONFIG_GPIOLIB` disabled (no link error, `-ENOSYS` at probe) - [Phase 3] `git describe HEAD`: v6.18.43; `make kernelversion`: 6.18.43 - [Phase 3] `git merge-base --is-ancestor ae3aa8cf5fd5 HEAD`: NOT IN TREE - [Phase 3] `d003d9bb44da1` (patch 3, S6E3HA2 GPIOLIB) confirmed in tree - [Phase 3] `3139b806923b1` (s6e3ha8 unmet dependency) confirmed in tree - [Phase 4] `b4 dig -c ae3aa8cf5fd5 -a`: found v1/v2 series on lore - [Phase 4] UNVERIFIED: `b4 dig -w` failed; lore WebFetch blocked by Anubis - [Phase 5] Grep confirmed all 5 drivers in `Makefile` and use GPIO consumer APIs - [Phase 6] Grep of `Kconfig`: 5 panels missing GPIOLIB dependency in 6.18.43 - [Phase 6] `JDI_LPM102A188A` and `RAYDIUM_RM69380` already have GPIOLIB - [Phase 7] Neil Armstrong is drm/panel maintainer (Reviewed-by) - [Phase 8] Failure mode: probe `-ENOSYS`, display broken; severity MEDIUM - [Phase 8] Typical ARM defconfigs: GPIOLIB usually enabled; impact lower for default configs **YES**The background check finished: upstream commit `ae3aa8cf5fd5` is **not** in the current 6.18.43 tree, so the GPIOLIB Kconfig fix still needs to be backported. The five affected panel drivers (`EBBG_FT8719`, `LG_SW43408`, `NOVATEK_NT36672A/E`, `VISIONOX_RM69299`) are still missing the `depends on GPIOLIB` entries in this tree. Verdict from the analysis: **YES** for stable backport. drivers/gpu/drm/panel/Kconfig | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig index 7354dc85a6aa7..967265ed6fc96 100644 --- a/drivers/gpu/drm/panel/Kconfig +++ b/drivers/gpu/drm/panel/Kconfig @@ -107,6 +107,7 @@ config DRM_PANEL_BOE_TV101WUM_LL2 config DRM_PANEL_EBBG_FT8719 tristate "EBBG FT8719 panel driver" + depends on GPIOLIB depends on OF depends on DRM_MIPI_DSI depends on BACKLIGHT_CLASS_DEVICE @@ -316,7 +317,8 @@ config DRM_PANEL_JADARD_JD9365DA_H3 config DRM_PANEL_JDI_LPM102A188A tristate "JDI LPM102A188A DSI panel" - depends on OF && GPIOLIB + depends on GPIOLIB + depends on OF depends on DRM_MIPI_DSI depends on BACKLIGHT_CLASS_DEVICE help @@ -418,6 +420,7 @@ config DRM_PANEL_LG_LG4573 config DRM_PANEL_LG_SW43408 tristate "LG SW43408 panel" + depends on GPIOLIB depends on OF depends on DRM_MIPI_DSI depends on BACKLIGHT_CLASS_DEVICE @@ -522,6 +525,7 @@ config DRM_PANEL_NOVATEK_NT36523 config DRM_PANEL_NOVATEK_NT36672A tristate "Novatek NT36672A DSI panel" + depends on GPIOLIB depends on OF depends on DRM_MIPI_DSI depends on BACKLIGHT_CLASS_DEVICE @@ -532,6 +536,7 @@ config DRM_PANEL_NOVATEK_NT36672A config DRM_PANEL_NOVATEK_NT36672E tristate "Novatek NT36672E DSI panel" + depends on GPIOLIB depends on OF depends on DRM_MIPI_DSI depends on BACKLIGHT_CLASS_DEVICE @@ -660,7 +665,8 @@ config DRM_PANEL_RAYDIUM_RM692E5 config DRM_PANEL_RAYDIUM_RM69380 tristate "Raydium RM69380-based DSI panel" - depends on OF && GPIOLIB + depends on GPIOLIB + depends on OF depends on DRM_MIPI_DSI depends on BACKLIGHT_CLASS_DEVICE help @@ -1118,6 +1124,7 @@ config DRM_PANEL_VISIONOX_R66451 config DRM_PANEL_VISIONOX_RM69299 tristate "Visionox RM69299" + depends on GPIOLIB depends on OF depends on DRM_MIPI_DSI help -- 2.53.0
