[PATCH v10 12/13] drm/atomic-helper: Re-order bridge chain pre-enable and post-disable

Aradhya Bhatia
2025-02-26T15:58:12Z

Move the bridge pre_enable call before crtc enable, and the bridge
post_disable call after the crtc disable.

The sequence of enable after this patch will look like:

bridge[n]_pre_enable
...
bridge[1]_pre_enable

crtc_enable
encoder_enable

bridge[1]_enable
...
bridge[n]_enable

And, the disable sequence for the display pipeline will look like:

bridge[n]_disable
...
bridge[1]_disable

encoder_disable
crtc_disable

bridge[1]_post_disable
...
bridge[n]_post_disable

The definition of bridge pre_enable hook says that,
"The display pipe (i.e. clocks and timing signals) feeding this bridge
will not yet be running when this callback is called".

Since CRTC is also a source feeding the bridge, it should not be enabled
before the bridges in the pipeline are pre_enabled. Fix that by
re-ordering the sequence of bridge pre_enable and bridge post_disable.

Acked-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Tested-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: Aradhya Bhatia <a-bhatia1@ti.com>
Signed-off-by: Aradhya Bhatia <aradhya.bhatia@linux.dev>
---
drivers/gpu/drm/drm_atomic_helper.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index d6a14e0c3e93..431a84a007aa 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -1336,9 +1336,9 @@ disable_outputs(struct drm_device *dev, struct drm_atomic_state *state)
{
encoder_bridge_disable(dev, state);

- encoder_bridge_post_disable(dev, state);
-
crtc_disable(dev, state);
+
+ encoder_bridge_post_disable(dev, state);
}

/**
@@ -1674,10 +1674,10 @@ encoder_bridge_enable(struct drm_device *dev, struct drm_atomic_state *state)
void drm_atomic_helper_commit_modeset_enables(struct drm_device *dev,
struct drm_atomic_state *state)
{
- crtc_enable(dev, state);
-
encoder_bridge_pre_enable(dev, state);

+ crtc_enable(dev, state);
+
encoder_bridge_enable(dev, state);

drm_atomic_helper_commit_writebacks(dev, state);
--
2.34.1