[PATCH v10 7/9] drm/msm/dpu1: Carry the mixers over to created CRTC states

[Maxime Ripard <mripard@kernel.org>]

drm_atomic_commit_fill_with_defaults() builds its commits out of
states created through atomic_create_state() instead of duplicating
the current state. A created CRTC state comes with no mixers, while a
duplicated state carries the ones currently assigned, since the
duplication copies the whole state.

dpu_crtc_atomic_check() only goes through dpu_crtc_assign_resources()
when the mode, the connectors or the color management properties
changed, so a CRTC that keeps its configuration with a created state
runs with no mixers at all.

Copy the mixers of the current state over when the new state has
none, like a duplicated state would have carried them. This is a
no-op for duplicated states, which already have them.

Only do so for a CRTC that stays enabled. dpu_crtc_assign_resources()
returns right after dpu_rm_release() for a disabled one, leaving the
mixers it just released behind in the state it was given, and those
must not be handed over to a new state where the consumers that don't
check the CRTC enablement could reach hardware reassigned since.

Signed-off-by: Maxime Ripard <mripard@kernel.org>

---

To: Rob Clark <robin.clark@oss.qualcomm.com>
To: Dmitry Baryshkov <lumag@kernel.org>
Cc: Abhinav Kumar <abhinav.kumar@linux.dev>
Cc: Jessica Zhang <jesszhan0024@gmail.com>
Cc: freedreno@lists.freedesktop.org
---
 drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
index 77a2d1f6700d..a99f6761035f 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
@@ -1538,10 +1538,33 @@ static int dpu_crtc_atomic_check(struct drm_crtc *crtc,
 	if (crtc_state->mode_changed || crtc_state->connectors_changed ||
 	    crtc_state->color_mgmt_changed) {
 		rc = dpu_crtc_assign_resources(crtc, crtc_state);
 		if (rc < 0)
 			return rc;
+	} else if (crtc_state->enable && !cstate->num_mixers) {
+		struct dpu_crtc_state *old_cstate =
+			to_dpu_crtc_state(drm_atomic_get_old_crtc_state(state,
+									crtc));
+
+		/*
+		 * A CRTC that keeps its configuration keeps its mixers.
+		 * A duplicated state carries them over, but a state
+		 * created through atomic_create_state() comes with
+		 * none, so copy them from the current state like a
+		 * duplicated state would, to make sure the checks and
+		 * the commit see the mixers in use.
+		 *
+		 * Only do so for a CRTC that stays enabled:
+		 * dpu_crtc_assign_resources() returns right after
+		 * dpu_rm_release() for a disabled one, leaving the mixers
+		 * it just released behind in the state it was given.
+		 */
+		if (old_cstate->num_mixers) {
+			cstate->num_mixers = old_cstate->num_mixers;
+			memcpy(cstate->mixers, old_cstate->mixers,
+			       sizeof(cstate->mixers));
+		}
 	}
 
 	if (crtc_state->planes_changed || crtc_state->zpos_changed) {
 		if (dpu_use_virtual_planes)
 			rc = dpu_crtc_reassign_planes(crtc, crtc_state);

-- 
2.56.0