drm/tidss: Fix enable/disable order

TI's OLDI and DSI encoders need to be set up before the crtc is enabled,
but the DRM helpers will enable the crtc first. This causes various
issues on TI platforms, like visual artifacts or crtc sync lost
warnings.

Thus drm_atomic_helper_commit_modeset_enables() and
drm_atomic_helper_commit_modeset_disables() cannot be used, as they
enable the crtc before bridges' pre-enable, and disable the crtc after
bridges' post-disable.

Open code the drm_atomic_helper_commit_modeset_enables() and
drm_atomic_helper_commit_modeset_disables(), and first call the bridges'
pre-enables, then crtc enable, then bridges' post-enable (and vice versa
for disable).

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Cc: stable@vger.kernel.org # v6.17+
Fixes: c9b1150a68d9 ("drm/atomic-helper: Re-order bridge chain pre-enable and post-disable")
Reviewed-by: Aradhya Bhatia <aradhya.bhatia@linux.dev>
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Tested-by: Linus Walleij <linusw@kernel.org>
Signed-off-by: Linus Walleij <linusw@kernel.org>
Link: https://patch.msgid.link/20251205-drm-seq-fix-v1-4-fda68fa1b3de@ideasonboard.com

diff --git a/drivers/gpu/drm/tidss/tidss_kms.c b/drivers/gpu/drm/tidss/tidss_kms.c
index 86eb5d97410bedced57129c2bbcd35f1719424c2..8bb93194e5ac686050c47f986b8cb6063eae22d3 100644 (file)
--- a/drivers/gpu/drm/tidss/tidss_kms.c
+++ b/drivers/gpu/drm/tidss/tidss_kms.c
@@ -26,9 +26,33 @@ static void tidss_atomic_commit_tail(struct drm_atomic_state *old_state)
 
        tidss_runtime_get(tidss);
 
-       drm_atomic_helper_commit_modeset_disables(ddev, old_state);
-       drm_atomic_helper_commit_planes(ddev, old_state, DRM_PLANE_COMMIT_ACTIVE_ONLY);
-       drm_atomic_helper_commit_modeset_enables(ddev, old_state);
+       /*
+        * TI's OLDI and DSI encoders need to be set up before the crtc is
+        * enabled. Thus drm_atomic_helper_commit_modeset_enables() and
+        * drm_atomic_helper_commit_modeset_disables() cannot be used here, as
+        * they enable the crtc before bridges' pre-enable, and disable the crtc
+        * after bridges' post-disable.
+        *
+        * Open code the functions here and first call the bridges' pre-enables,
+        * then crtc enable, then bridges' post-enable (and vice versa for
+        * disable).
+        */
+
+       drm_atomic_helper_commit_encoder_bridge_disable(ddev, old_state);
+       drm_atomic_helper_commit_crtc_disable(ddev, old_state);
+       drm_atomic_helper_commit_encoder_bridge_post_disable(ddev, old_state);
+
+       drm_atomic_helper_update_legacy_modeset_state(ddev, old_state);
+       drm_atomic_helper_calc_timestamping_constants(old_state);
+       drm_atomic_helper_commit_crtc_set_mode(ddev, old_state);
+
+       drm_atomic_helper_commit_planes(ddev, old_state,
+                                       DRM_PLANE_COMMIT_ACTIVE_ONLY);
+
+       drm_atomic_helper_commit_encoder_bridge_pre_enable(ddev, old_state);
+       drm_atomic_helper_commit_crtc_enable(ddev, old_state);
+       drm_atomic_helper_commit_encoder_bridge_enable(ddev, old_state);
+       drm_atomic_helper_commit_writebacks(ddev, old_state);
 
        drm_atomic_helper_commit_hw_done(old_state);
        drm_atomic_helper_wait_for_flip_done(ddev, old_state);