Re: [PATCH v4 01/10] drm/damage-helper: Do not alter damage clips on modeset, but ignore them

[Javier Martinez Canillas <javierm@redhat.com>]

Thomas Zimmermann <tzimmermann@suse.de> writes:

Hello Thomas,

> User space supplies rectangles for damage clipping in a plane property.
> For full mode sets, drivers still require a full plane update. In this
> case, leave the information as-is and set the ignore_damage_clips flag
> instead. The damage iterator will later ignore any damage information.
>
> Also fixes a bug where ignore_damage_clips was not cleared across plane-
> state duplications.
>
> Leaving the damage information as-is might be helpful to drivers that
> benefit from this information even on full modesets (e.g., for cache
> management). It will also help with consolidating the damage-handling
> logic.
>
> Also add a new unit test that evaluates the ignore_damage_clips flag. It
> sets two damage clips plus the flag and tests if the reported damage
> covers the entire framebuffer.
>
> v4:
> - slightly reword the commit description
>
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> Fixes: 35ed38d58257 ("drm: Allow drivers to indicate the damage helpers to ignore damage clips")
> Acked-by: Zack Rusin <zack.rusin@broadcom.com>
> Cc: dri-devel@lists.freedesktop.org
> Cc: <stable@vger.kernel.org> # v6.10+
> ---
>  drivers/gpu/drm/drm_atomic_state_helper.c     |  1 +
>  drivers/gpu/drm/drm_damage_helper.c           |  6 ++--
>  .../gpu/drm/tests/drm_damage_helper_test.c    | 28 +++++++++++++++++++
>  3 files changed, 31 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_atomic_state_helper.c b/drivers/gpu/drm/drm_atomic_state_helper.c
> index cc70508d4fdb..84d5231ccac1 100644
> --- a/drivers/gpu/drm/drm_atomic_state_helper.c
> +++ b/drivers/gpu/drm/drm_atomic_state_helper.c
> @@ -359,6 +359,7 @@ void __drm_atomic_helper_plane_duplicate_state(struct drm_plane *plane,
>  	state->fence = NULL;
>  	state->commit = NULL;
>  	state->fb_damage_clips = NULL;
> +	state->ignore_damage_clips = false;
>  	state->color_mgmt_changed = false;
>  }

I would split this as a separate patch since is the bug you are fixing for
commit 35ed38d58257 ("drm: Allow drivers to indicate the damage helpers to
ignore damage clips").

>  EXPORT_SYMBOL(__drm_atomic_helper_plane_duplicate_state);
> diff --git a/drivers/gpu/drm/drm_damage_helper.c b/drivers/gpu/drm/drm_damage_helper.c
> index 74a7f4252ecf..945fac8dc27b 100644
> --- a/drivers/gpu/drm/drm_damage_helper.c
> +++ b/drivers/gpu/drm/drm_damage_helper.c
> @@ -78,10 +78,8 @@ void drm_atomic_helper_check_plane_damage(struct drm_atomic_commit *state,
>  		if (WARN_ON(!crtc_state))
>  			return;
>  
> -		if (drm_atomic_crtc_needs_modeset(crtc_state)) {
> -			drm_property_blob_put(plane_state->fb_damage_clips);
> -			plane_state->fb_damage_clips = NULL;
> -		}
> +		if (drm_atomic_crtc_needs_modeset(crtc_state))
> +			plane_state->ignore_damage_clips = true;
>  	}
>  }

This makes sense to me as well and I agree that re-using the flag for this
is better than making plane_state->fb_damage_clips == NULL the condition.

As mentioned though, I would make it a separate patch. Both changes look
good to me:

Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>

-- 
Best regards,

Javier Martinez Canillas
Core Platforms
Red Hat