[PATCH] drm/amd/display: Fix overlay validation by considering cursors

[Rodrigo Siqueira]

A few weeks ago, we saw a two cursor issue in a ChromeOS system. We
fixed it in the commit:

 drm/amd/display: Fix two cursor duplication when using overlay
 (read the commit message for more details)

After this change, we noticed that some IGT subtests related to
kms_plane and kms_plane_scaling started to fail. After investigating
this issue, we noticed that all subtests that fail have a primary plane
covering the overlay plane, which is currently rejected by amdgpu dm.
Fail those IGT tests highlight that our verification was too broad and
compromises the overlay usage in our drive. This patch fixes this issue
by ensuring that we only reject commits where the primary plane is not
fully covered by the overlay when the cursor hardware is enabled. With
this fix, all IGT tests start to pass again, which means our overlay
support works as expected.

Cc: Tianci.Yin <tianci.yin at amd.com>
Cc: Harry Wentland <harry.wentland at amd.com>
Cc: Nicholas Choi <nicholas.choi at amd.com>
Cc: Bhawanpreet Lakha <bhawanpreet.lakha at amd.com>
Cc: Nicholas Kazlauskas <Nicholas.Kazlauskas at amd.com>
Cc: Mark Yacoub <markyacoub at google.com>
Cc: Daniel Wheeler <daniel.wheeler at amd.com>

Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira at amd.com>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index ccd67003b120..9c2537a17a7b 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -10067,7 +10067,7 @@ static int validate_overlay(struct drm_atomic_state *state)
 	int i;
 	struct drm_plane *plane;
 	struct drm_plane_state *old_plane_state, *new_plane_state;
-	struct drm_plane_state *primary_state, *overlay_state = NULL;
+	struct drm_plane_state *primary_state, *cursor_state, *overlay_state = NULL;
 
 	/* Check if primary plane is contained inside overlay */
 	for_each_oldnew_plane_in_state_reverse(state, plane, old_plane_state, new_plane_state, i) {
@@ -10097,6 +10097,14 @@ static int validate_overlay(struct drm_atomic_state *state)
 	if (!primary_state->crtc)
 		return 0;
 
+	/* check if cursor plane is enabled */
+	cursor_state = drm_atomic_get_plane_state(state, overlay_state->crtc->cursor);
+	if (IS_ERR(cursor_state))
+		return PTR_ERR(cursor_state);
+
+	if (drm_atomic_plane_disabling(plane->state, cursor_state))
+		return 0;
+
 	/* Perform the bounds check to ensure the overlay plane covers the primary */
 	if (primary_state->crtc_x < overlay_state->crtc_x ||
 	    primary_state->crtc_y < overlay_state->crtc_y ||
-- 
2.25.1