[PATCH v9 08/10] drm/msm/dpu1: Carry the mixers over to created CRTC states

From: Maxime Ripard

Date: Tue Nov 10 2026 - 11:12:14 EST


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 and the CTLs 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.

Signed-off-by: Maxime Ripard <mripard@xxxxxxxxxx>

---

To: Rob Clark <robin.clark@xxxxxxxxxxxxxxxx>
To: Dmitry Baryshkov <lumag@xxxxxxxxxx>
Cc: Abhinav Kumar <abhinav.kumar@xxxxxxxxx>
Cc: Jessica Zhang <jesszhan0024@xxxxxxxxx>
Cc: freedreno@xxxxxxxxxxxxxxxxxxxxx
---
drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c | 21 +++++++++++++++++++++
1 file changed, 21 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..97deadc976ed 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
@@ -1538,10 +1538,31 @@ 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 (!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.
+ */
+ if (old_cstate->num_mixers) {
+ cstate->num_mixers = old_cstate->num_mixers;
+ memcpy(cstate->mixers, old_cstate->mixers,
+ sizeof(cstate->mixers));
+ cstate->num_ctls = old_cstate->num_ctls;
+ memcpy(cstate->hw_ctls, old_cstate->hw_ctls,
+ sizeof(cstate->hw_ctls));
+ }
}

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