[PATCH v2] drm/gud: Ignore damage clips in full update mode

[Sophie D <patches@scd31.com>]

When running in full update mode, previously small updates (such as
moving the mouse across the screen) would cause many full frames to be
generated. This would bog down the bus and lower the effective framerate
significantly - I was seeing a drop from 60 FPS to 2 FPS.

Set ignore_damage_clips in full update mode so the damage iterator
yields a single full-plane rectangle instead of one per clip.

Fixes: 73cfd166e045 ("drm/gud: Replace simple display pipe with DRM atomic helpers")
Cc: <stable@vger.kernel.org> # 6.18.x
Signed-off-by: Sophie D <patches@scd31.com>
---
v2: set ignore_damage_clips in atomic_check instead of merging clips in
    atomic_update (Thomas Zimmermann)

 drivers/gpu/drm/gud/gud_pipe.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/gud/gud_pipe.c b/drivers/gpu/drm/gud/gud_pipe.c
index 5ef887d84..3388fdc8e 100644
--- a/drivers/gpu/drm/gud/gud_pipe.c
+++ b/drivers/gpu/drm/gud/gud_pipe.c
@@ -482,6 +482,9 @@ int gud_plane_atomic_check(struct drm_plane *plane,
 	if (!new_plane_state->visible)
 		return 0;
 
+	if (gdrm->flags & GUD_DISPLAY_FLAG_FULL_UPDATE)
+		new_plane_state->ignore_damage_clips = true;
+
 	if (old_plane_state->rotation != new_plane_state->rotation)
 		crtc_state->mode_changed = true;
 
-- 
2.55.0