Re: [PATCH v3 4/4] drm/i915/display: Error codes for async flip failures

[Maarten Lankhorst <maarten.lankhorst@linux.intel.com>]

Hey,

I'm not entirely sold on the design, it's way more complicated than it should be, it should be trivial to add any amount of error messages.

Replace return -EINVAL; with return drm_atomic_error_einval(state, class, "string");
Where class may be an enum, but in a way more generic way than currently specified, for example "invalid use of api", "requires modeset", "invalid arguments", "driver limitations", "async flip not possible".

The drm_atomic_error_einval() would set class and str as appropriate, and then return -EINVAL.

That's probably all we should need here.

Kind regards,
~Maarten

Den 2025-08-22 kl. 09:00, skrev Arun R Murthy:
> For failures in async flip atomic check/commit path return user readable
> error codes in struct drm_atomic_state.
> 
> Signed-off-by: Arun R Murthy <arun.r.murthy@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_display.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index c1a3a95c65f0b66c24ddd64f47dfdc67bbde86c9..5e23f4fc747bd01fa05eba63661bf7279b083317 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -5950,6 +5950,7 @@ static int intel_async_flip_check_uapi(struct intel_atomic_state *state,
>  		drm_dbg_kms(display->drm,
>  			    "[CRTC:%d:%s] modeset required\n",
>  			    crtc->base.base.id, crtc->base.name);
> +		state->base.error_code->failure_flags = DRM_MODE_ATOMIC_CRTC_NEED_FULL_MODESET;
>  		return -EINVAL;
>  	}
>  
> @@ -6019,6 +6020,7 @@ static int intel_async_flip_check_hw(struct intel_atomic_state *state, struct in
>  		drm_dbg_kms(display->drm,
>  			    "[CRTC:%d:%s] modeset required\n",
>  			    crtc->base.base.id, crtc->base.name);
> +		state->base.error_code->failure_flags = DRM_MODE_ATOMIC_CRTC_NEED_FULL_MODESET;
>  		return -EINVAL;
>  	}
>  
> @@ -6061,6 +6063,8 @@ static int intel_async_flip_check_hw(struct intel_atomic_state *state, struct in
>  				    plane->base.base.id, plane->base.name,
>  				    &new_plane_state->hw.fb->format->format,
>  				    new_plane_state->hw.fb->modifier);
> +			state->base.error_code->failure_flags =
> +				DRM_MODE_ATOMIC_ASYNC_MODIFIER_NOT_SUPPORTED;
>  			return -EINVAL;
>  		}
>  
>