[PATCH] drm/i915: replace select with dependency for visible DEBUG_OBJECTS

[PATCH] drm/i915: replace select with dependency for visible DEBUG_OBJECTS

[Julian Braha]

DRM_I915_SW_FENCE_DEBUG_OBJECTS currently selects DEBUG_OBJECTS even though
DEBUG_OBJECTS is visible to users. Other config options use 'depends on'
for DEBUG_OBJECTS, so let's do the same here.

This select-visible Kconfig misusage was detected by Kconfirm, a static
analysis tool for Kconfig.

Signed-off-by: Julian Braha <julianbraha@gmail.com>
---
 drivers/gpu/drm/i915/Kconfig.debug | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/Kconfig.debug b/drivers/gpu/drm/i915/Kconfig.debug
index 52a3a59b4ba2..028a2c97361d 100644
--- a/drivers/gpu/drm/i915/Kconfig.debug
+++ b/drivers/gpu/drm/i915/Kconfig.debug
@@ -153,7 +153,7 @@ config DRM_I915_TRACE_GTT
 config DRM_I915_SW_FENCE_DEBUG_OBJECTS
 	bool "Enable additional driver debugging for fence objects"
 	depends on DRM_I915
-	select DEBUG_OBJECTS
+	depends on DEBUG_OBJECTS
 	default n
 	help
 	  Choose this option to turn on extra driver debugging that may affect
-- 
2.53.0

Claude review: drm/i915: replace select with dependency for visible DEBUG_OBJECTS

[Claude Code Review Bot]

Patch Review

**The change:**
```diff
-	select DEBUG_OBJECTS
+	depends on DEBUG_OBJECTS
```

**Issue 1 (functional regression — blocker):** `DRM_I915_DEBUG` (Kconfig.debug:36) contains:

```
select DRM_I915_SW_FENCE_DEBUG_OBJECTS
```

With the old code, enabling `DRM_I915_DEBUG` would pull in `DRM_I915_SW_FENCE_DEBUG_OBJECTS`, which in turn pulled in `DEBUG_OBJECTS` via `select`. The full debug chain worked automatically.

After this patch, `DRM_I915_SW_FENCE_DEBUG_OBJECTS` now `depends on DEBUG_OBJECTS`. When Kconfig processes the `select DRM_I915_SW_FENCE_DEBUG_OBJECTS` from `DRM_I915_DEBUG`, if `DEBUG_OBJECTS` is not already enabled, the `select` is silently ignored because the dependency is unsatisfied. This means a developer enabling `DRM_I915_DEBUG` (the umbrella debug option) will silently lose sw_fence debug object tracking — the opposite of the expected behavior.

To fix this properly, the author needs to also add `select DEBUG_OBJECTS` (or `depends on DEBUG_OBJECTS`) to `DRM_I915_DEBUG` itself, so that the dependency is satisfied before `DRM_I915_SW_FENCE_DEBUG_OBJECTS` is selected. For example:

```
config DRM_I915_DEBUG
    ...
    select DEBUG_OBJECTS
    select DRM_I915_SW_FENCE_DEBUG_OBJECTS
```

Or alternatively, `DRM_I915_DEBUG` could switch from `select DRM_I915_SW_FENCE_DEBUG_OBJECTS` to `select DRM_I915_SW_FENCE_DEBUG_OBJECTS if DEBUG_OBJECTS`, making the dependency chain explicit.

**Issue 2 (minor — usability):** `DEBUG_OBJECTS` itself has dependencies (`depends on PREEMPT_COUNT || !DEFERRED_STRUCT_PAGE_INIT` and `depends on DEBUG_KERNEL`). With the old `select`, these were irrelevant for the i915 path — the symbol was force-enabled. Now users must ensure `DEBUG_KERNEL` (and potentially `PREEMPT_COUNT`) are enabled for `DRM_I915_SW_FENCE_DEBUG_OBJECTS` to even appear in menuconfig. This may be intentional (making the dependency explicit), but it changes the usability for developers who just want fence debugging without the full `DRM_I915_DEBUG` umbrella.

**Nit:** The commit message says "Other config options use 'depends on' for DEBUG_OBJECTS" — this is true, but all those other options (`DEBUG_OBJECTS_SELFTEST`, `DEBUG_OBJECTS_FREE`, etc. in `lib/Kconfig.debug`) are children of the `DEBUG_OBJECTS` menu and are never force-selected by anything. The i915 case is different because of the `select` chain from `DRM_I915_DEBUG`, so the analogy doesn't fully hold.

---
Generated by Claude Code Patch Reviewer

Claude review: drm/i915: replace select with dependency for visible DEBUG_OBJECTS

[Claude Code Review Bot]

Overall Series Review

Subject: drm/i915: replace select with dependency for visible DEBUG_OBJECTS
Author: Julian Braha <julianbraha@gmail.com>
Patches: 1
Reviewed: 2026-05-05T08:46:43.221055

---

This is a single-patch series changing `DRM_I915_SW_FENCE_DEBUG_OBJECTS` from `select DEBUG_OBJECTS` to `depends on DEBUG_OBJECTS`. The stated rationale is that `select` should not be used on user-visible symbols. While that Kconfig convention is real, this patch has a **functional regression** that makes it unsuitable for merging as-is: `DRM_I915_DEBUG` uses `select DRM_I915_SW_FENCE_DEBUG_OBJECTS` (line 62 of `Kconfig.debug`), and after this change, that `select` will silently fail whenever `DEBUG_OBJECTS` is not already enabled — breaking the intended behavior of the umbrella `DRM_I915_DEBUG` option.

**Verdict: Needs rework.**

---

---
Generated by Claude Code Patch Reviewer