[PATCH] drm/i915/fbdev: fix link failure without FBDEV emulation

[PATCH] drm/i915/fbdev: fix link failure without FBDEV emulation

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

If CONFIG_DRM_FBDEV_EMULATION is disabled but CONFIG_FRAMEBUFFER_CONSOLE
is turned on, the i915 driver now fails to link:

ERROR: modpost: "intel_fbdev_fb_prefer_stolen" [drivers/gpu/drm/i915/i915.ko] undefined!

Fix the contition to include a check for the symbol that controls compilation
of intel_fbdev_fb.c.

Fixes: 94c7d2861292 ("drm/i915/fbdev: Extract intel_fbdev_fb_prefer_stolen()")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/gpu/drm/i915/i915_initial_plane.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_initial_plane.c b/drivers/gpu/drm/i915/i915_initial_plane.c
index 5594548f51d8..390a9248d631 100644
--- a/drivers/gpu/drm/i915/i915_initial_plane.c
+++ b/drivers/gpu/drm/i915/i915_initial_plane.c
@@ -115,7 +115,8 @@ initial_plane_vma(struct drm_i915_private *i915,
 	 * important and we should probably use that space with FBC or other
 	 * features.
 	 */
-	if (IS_ENABLED(CONFIG_FRAMEBUFFER_CONSOLE) &&
+	if (IS_ENABLED(CONFIG_DRM_FBDEV_EMULATION) &&
+	    IS_ENABLED(CONFIG_FRAMEBUFFER_CONSOLE) &&
 	    mem == i915->mm.stolen_region &&
 	    !intel_fbdev_fb_prefer_stolen(&i915->drm, size)) {
 		drm_dbg_kms(&i915->drm, "Initial FB size exceeds half of stolen, discarding\n");
-- 
2.39.5

Re: [PATCH] drm/i915/fbdev: fix link failure without FBDEV emulation

[Thomas Zimmermann]

Hi

Am 04.03.26 um 09:36 schrieb Arnd Bergmann:
> From: Arnd Bergmann <arnd@arndb.de>
>
> If CONFIG_DRM_FBDEV_EMULATION is disabled but CONFIG_FRAMEBUFFER_CONSOLE
> is turned on, the i915 driver now fails to link:
>
> ERROR: modpost: "intel_fbdev_fb_prefer_stolen" [drivers/gpu/drm/i915/i915.ko] undefined!
>
> Fix the contition to include a check for the symbol that controls compilation
> of intel_fbdev_fb.c.
>
> Fixes: 94c7d2861292 ("drm/i915/fbdev: Extract intel_fbdev_fb_prefer_stolen()")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>   drivers/gpu/drm/i915/i915_initial_plane.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_initial_plane.c b/drivers/gpu/drm/i915/i915_initial_plane.c
> index 5594548f51d8..390a9248d631 100644
> --- a/drivers/gpu/drm/i915/i915_initial_plane.c
> +++ b/drivers/gpu/drm/i915/i915_initial_plane.c
> @@ -115,7 +115,8 @@ initial_plane_vma(struct drm_i915_private *i915,
>   	 * important and we should probably use that space with FBC or other
>   	 * features.
>   	 */
> -	if (IS_ENABLED(CONFIG_FRAMEBUFFER_CONSOLE) &&
> +	if (IS_ENABLED(CONFIG_DRM_FBDEV_EMULATION) &&
> +	    IS_ENABLED(CONFIG_FRAMEBUFFER_CONSOLE) &&

It's possible to run fbdev without the console. So if I'm not mistaken, 
only CONFIG_DRM_FBDEV_EMULATION would be correct.

Best regards
Thomas


>   	    mem == i915->mm.stolen_region &&
>   	    !intel_fbdev_fb_prefer_stolen(&i915->drm, size)) {
>   		drm_dbg_kms(&i915->drm, "Initial FB size exceeds half of stolen, discarding\n");

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
GF: Jochen Jaser, Andrew McDonald, Werner Knoblich, (HRB 36809, AG Nürnberg)

Claude review: drm/i915/fbdev: fix link failure without FBDEV emulation

[Claude Code Review Bot]

Overall Series Review

Subject: drm/i915/fbdev: fix link failure without FBDEV emulation
Author: Arnd Bergmann <arnd@kernel.org>
Patches: 2
Reviewed: 2026-03-05T13:43:28.995608

---

This is a single-patch fix for a link error that occurs when `CONFIG_DRM_FBDEV_EMULATION=n` but `CONFIG_FRAMEBUFFER_CONSOLE=y`. The function `intel_fbdev_fb_prefer_stolen()` lives in `intel_fbdev_fb.c`, which is only compiled when `CONFIG_DRM_FBDEV_EMULATION` is enabled (confirmed by the Makefile at line 325-327). The original code only guarded the call with `IS_ENABLED(CONFIG_FRAMEBUFFER_CONSOLE)`, which is insufficient since `CONFIG_FRAMEBUFFER_CONSOLE` can be enabled independently.

The fix is correct, minimal, and well-targeted. Adding the `IS_ENABLED(CONFIG_DRM_FBDEV_EMULATION)` check ensures the call to `intel_fbdev_fb_prefer_stolen()` is compiled out when the object file providing that symbol isn't built.

**Verdict: Good to merge.**

---
Generated by Claude Code Patch Reviewer

Claude review: drm/i915/fbdev: fix link failure without FBDEV emulation

[Claude Code Review Bot]

Patch Review

**Correctness:** The fix is correct. The condition now reads:

```c
if (IS_ENABLED(CONFIG_DRM_FBDEV_EMULATION) &&
    IS_ENABLED(CONFIG_FRAMEBUFFER_CONSOLE) &&
    mem == i915->mm.stolen_region &&
    !intel_fbdev_fb_prefer_stolen(&i915->drm, size)) {
```

Since C short-circuit evaluation will skip `intel_fbdev_fb_prefer_stolen()` when `CONFIG_DRM_FBDEV_EMULATION` is disabled, and the compiler will eliminate the dead code (including the reference to the undefined symbol), this resolves the link error.

**Minor nit:** The commit message has a typo: "contition" should be "condition". This is cosmetic and doesn't affect the fix itself.

**Fixes tag:** Correctly references the commit that introduced the regression (94c7d2861292).

**Scope:** Minimal one-line change (adding one check), appropriately scoped for a build fix.

**No other concerns.** The patch is straightforward and correct.

---
Generated by Claude Code Patch Reviewer