Re: [PATCH v2 1/1] drm: use drm_warn() in validate_blend_mode_for_alpha_formats()

[Daniel Stone]

Hi Leandro,

On Fri, 31 Jul 2026 at 16:43, Leandro Ribeiro
<leandro.ribeiro@xxxxxxxxxxxxx> wrote:
> Commit 860e748bddcc ("drm: ensure blend mode supported if pixel format
> with alpha exposed") introduced a WARN() to let driver developers know
> that a previously valid behavior should now be changed.
>
> But WARN() should not be used for that, as it's a kernel warning report
> mechanism for conditions that are not expected to happen. It also
> produces a stack trace. Instead, a simple warning-level log message
> should have been used, as drivers were expected to trigger the
> condition.
>
> This is causing problems for fuzzers, as they may stop when encountering
> a "BUG:" or "WARNING:" in the logs.
>
> Replace WARN() with drm_warn() in this function, avoiding these issues.
>
> Fixes: 860e748bddcc ("drm: ensure blend mode supported if pixel format with alpha exposed")
> Signed-off-by: Leandro Ribeiro <leandro.ribeiro@xxxxxxxxxxxxx>

Thanks, this is:
Reviewed-by: Daniel Stone <daniels@xxxxxxxxxxxxx>

I'll fix up the newline when applying.

Cheers,
Daniel