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drm/atomic-helper: Re-order bridge chain pre-enable and post-disable

Browse source 
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.

While at it, update the drm bridge API documentation as well.

Acked-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Tested-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Tested-by: Alexander Sverdlin <alexander.sverdlin@siemens.com>
Signed-off-by: Aradhya Bhatia <a-bhatia1@ti.com>
Signed-off-by: Aradhya Bhatia <aradhya.bhatia@linux.dev>
Tested-by: Devarsh Thakkar <devarsht@ti.com>
Link: https://lore.kernel.org/r/20250605171524.27222-4-aradhya.bhatia@linux.dev
Signed-off-by: Maxime Ripard <mripard@kernel.org>
This commit is contained in:
Aradhya Bhatia 2025-06-05 22:45:23 +05:30 • committed by Maxime Ripard
parent d5bef6430c
commit c9b1150a68
No known key found for this signature in database
GPG key ID: 275FCE19A23DBE76
2 changed files with 187 additions and 70 deletions
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8
drivers/gpu/drm/drm_atomic_helper.c
View file

@ -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);

249
include/drm/drm_bridge.h
View file

@ -165,17 +165,33 @@ struct drm_bridge_funcs {
/**
* @disable:
*
* This callback should disable the bridge. It is called right before
* the preceding element in the display pipe is disabled. If the
* preceding element is a bridge this means it's called before that
* bridge's @disable vfunc. If the preceding element is a &drm_encoder
* it's called right before the &drm_encoder_helper_funcs.disable,
* &drm_encoder_helper_funcs.prepare or &drm_encoder_helper_funcs.dpms
* hook.
* The @disable callback should disable the bridge.
*
* The bridge can assume that the display pipe (i.e. clocks and timing
* signals) feeding it is still running when this callback is called.
*
*
* If the preceding element is a &drm_bridge, then this is called before
* that bridge is disabled via one of:
*
* - &drm_bridge_funcs.disable
* - &drm_bridge_funcs.atomic_disable
*
* If the preceding element of the bridge is a display controller, then
* this callback is called before the encoder is disabled via one of:
*
* - &drm_encoder_helper_funcs.atomic_disable
* - &drm_encoder_helper_funcs.prepare
* - &drm_encoder_helper_funcs.disable
* - &drm_encoder_helper_funcs.dpms
*
* and the CRTC is disabled via one of:
*
* - &drm_crtc_helper_funcs.prepare
* - &drm_crtc_helper_funcs.atomic_disable
* - &drm_crtc_helper_funcs.disable
* - &drm_crtc_helper_funcs.dpms.
*
* The @disable callback is optional.
*
* NOTE:
@ -188,17 +204,34 @@ struct drm_bridge_funcs {
/**
* @post_disable:
*
* This callback should disable the bridge. It is called right after the
* preceding element in the display pipe is disabled. If the preceding
* element is a bridge this means it's called after that bridge's
* @post_disable function. If the preceding element is a &drm_encoder
* it's called right after the encoder's
* &drm_encoder_helper_funcs.disable, &drm_encoder_helper_funcs.prepare
* or &drm_encoder_helper_funcs.dpms hook.
*
* The bridge must assume that the display pipe (i.e. clocks and timing
* signals) feeding it is no longer running when this callback is
* called.
* signals) feeding this bridge is no longer running when the
* @post_disable is called.
*
* This callback should perform all the actions required by the hardware
* after it has stopped receiving signals from the preceding element.
*
* If the preceding element is a &drm_bridge, then this is called after
* that bridge is post-disabled (unless marked otherwise by the
* @pre_enable_prev_first flag) via one of:
*
* - &drm_bridge_funcs.post_disable
* - &drm_bridge_funcs.atomic_post_disable
*
* If the preceding element of the bridge is a display controller, then
* this callback is called after the encoder is disabled via one of:
*
* - &drm_encoder_helper_funcs.atomic_disable
* - &drm_encoder_helper_funcs.prepare
* - &drm_encoder_helper_funcs.disable
* - &drm_encoder_helper_funcs.dpms
*
* and the CRTC is disabled via one of:
*
* - &drm_crtc_helper_funcs.prepare
* - &drm_crtc_helper_funcs.atomic_disable
* - &drm_crtc_helper_funcs.disable
* - &drm_crtc_helper_funcs.dpms
*
* The @post_disable callback is optional.
*
@ -241,18 +274,30 @@ struct drm_bridge_funcs {
/**
* @pre_enable:
*
* This callback should enable the bridge. It is called right before
* the preceding element in the display pipe is enabled. If the
* preceding element is a bridge this means it's called before that
* bridge's @pre_enable function. If the preceding element is a
* &drm_encoder it's called right before the encoder's
* &drm_encoder_helper_funcs.enable, &drm_encoder_helper_funcs.commit or
* &drm_encoder_helper_funcs.dpms hook.
*
* The display pipe (i.e. clocks and timing signals) feeding this bridge
* will not yet be running when this callback is called. The bridge must
* not enable the display link feeding the next bridge in the chain (if
* there is one) when this callback is called.
* will not yet be running when the @pre_enable is called.
*
* This callback should perform all the necessary actions to prepare the
* bridge to accept signals from the preceding element.
*
* If the preceding element is a &drm_bridge, then this is called before
* that bridge is pre-enabled (unless marked otherwise by
* @pre_enable_prev_first flag) via one of:
*
* - &drm_bridge_funcs.pre_enable
* - &drm_bridge_funcs.atomic_pre_enable
*
* If the preceding element of the bridge is a display controller, then
* this callback is called before the CRTC is enabled via one of:
*
* - &drm_crtc_helper_funcs.atomic_enable
* - &drm_crtc_helper_funcs.commit
*
* and the encoder is enabled via one of:
*
* - &drm_encoder_helper_funcs.atomic_enable
* - &drm_encoder_helper_funcs.enable
* - &drm_encoder_helper_funcs.commit
*
* The @pre_enable callback is optional.
*
@ -266,19 +311,31 @@ struct drm_bridge_funcs {
/**
* @enable:
*
* This callback should enable the bridge. It is called right after
* the preceding element in the display pipe is enabled. If the
* preceding element is a bridge this means it's called after that
* bridge's @enable function. If the preceding element is a
* &drm_encoder it's called right after the encoder's
* &drm_encoder_helper_funcs.enable, &drm_encoder_helper_funcs.commit or
* &drm_encoder_helper_funcs.dpms hook.
* The @enable callback should enable the bridge.
*
* The bridge can assume that the display pipe (i.e. clocks and timing
* signals) feeding it is running when this callback is called. This
* callback must enable the display link feeding the next bridge in the
* chain if there is one.
*
* If the preceding element is a &drm_bridge, then this is called after
* that bridge is enabled via one of:
*
* - &drm_bridge_funcs.enable
* - &drm_bridge_funcs.atomic_enable
*
* If the preceding element of the bridge is a display controller, then
* this callback is called after the CRTC is enabled via one of:
*
* - &drm_crtc_helper_funcs.atomic_enable
* - &drm_crtc_helper_funcs.commit
*
* and the encoder is enabled via one of:
*
* - &drm_encoder_helper_funcs.atomic_enable
* - &drm_encoder_helper_funcs.enable
* - drm_encoder_helper_funcs.commit
*
* The @enable callback is optional.
*
* NOTE:
@ -291,17 +348,30 @@ struct drm_bridge_funcs {
/**
* @atomic_pre_enable:
*
* This callback should enable the bridge. It is called right before
* the preceding element in the display pipe is enabled. If the
* preceding element is a bridge this means it's called before that
* bridge's @atomic_pre_enable or @pre_enable function. If the preceding
* element is a &drm_encoder it's called right before the encoder's
* &drm_encoder_helper_funcs.atomic_enable hook.
*
* The display pipe (i.e. clocks and timing signals) feeding this bridge
* will not yet be running when this callback is called. The bridge must
* not enable the display link feeding the next bridge in the chain (if
* there is one) when this callback is called.
* will not yet be running when the @atomic_pre_enable is called.
*
* This callback should perform all the necessary actions to prepare the
* bridge to accept signals from the preceding element.
*
* If the preceding element is a &drm_bridge, then this is called before
* that bridge is pre-enabled (unless marked otherwise by
* @pre_enable_prev_first flag) via one of:
*
* - &drm_bridge_funcs.pre_enable
* - &drm_bridge_funcs.atomic_pre_enable
*
* If the preceding element of the bridge is a display controller, then
* this callback is called before the CRTC is enabled via one of:
*
* - &drm_crtc_helper_funcs.atomic_enable
* - &drm_crtc_helper_funcs.commit
*
* and the encoder is enabled via one of:
*
* - &drm_encoder_helper_funcs.atomic_enable
* - &drm_encoder_helper_funcs.enable
* - &drm_encoder_helper_funcs.commit
*
* The @atomic_pre_enable callback is optional.
*/
@ -311,18 +381,31 @@ struct drm_bridge_funcs {
/**
* @atomic_enable:
*
* This callback should enable the bridge. It is called right after
* the preceding element in the display pipe is enabled. If the
* preceding element is a bridge this means it's called after that
* bridge's @atomic_enable or @enable function. If the preceding element
* is a &drm_encoder it's called right after the encoder's
* &drm_encoder_helper_funcs.atomic_enable hook.
* The @atomic_enable callback should enable the bridge.
*
* The bridge can assume that the display pipe (i.e. clocks and timing
* signals) feeding it is running when this callback is called. This
* callback must enable the display link feeding the next bridge in the
* chain if there is one.
*
* If the preceding element is a &drm_bridge, then this is called after
* that bridge is enabled via one of:
*
* - &drm_bridge_funcs.enable
* - &drm_bridge_funcs.atomic_enable
*
* If the preceding element of the bridge is a display controller, then
* this callback is called after the CRTC is enabled via one of:
*
* - &drm_crtc_helper_funcs.atomic_enable
* - &drm_crtc_helper_funcs.commit
*
* and the encoder is enabled via one of:
*
* - &drm_encoder_helper_funcs.atomic_enable
* - &drm_encoder_helper_funcs.enable
* - drm_encoder_helper_funcs.commit
*
* The @atomic_enable callback is optional.
*/
void (*atomic_enable)(struct drm_bridge *bridge,
@ -330,16 +413,32 @@ struct drm_bridge_funcs {
/**
* @atomic_disable:
*
* This callback should disable the bridge. It is called right before
* the preceding element in the display pipe is disabled. If the
* preceding element is a bridge this means it's called before that
* bridge's @atomic_disable or @disable vfunc. If the preceding element
* is a &drm_encoder it's called right before the
* &drm_encoder_helper_funcs.atomic_disable hook.
* The @atomic_disable callback should disable the bridge.
*
* The bridge can assume that the display pipe (i.e. clocks and timing
* signals) feeding it is still running when this callback is called.
*
* If the preceding element is a &drm_bridge, then this is called before
* that bridge is disabled via one of:
*
* - &drm_bridge_funcs.disable
* - &drm_bridge_funcs.atomic_disable
*
* If the preceding element of the bridge is a display controller, then
* this callback is called before the encoder is disabled via one of:
*
* - &drm_encoder_helper_funcs.atomic_disable
* - &drm_encoder_helper_funcs.prepare
* - &drm_encoder_helper_funcs.disable
* - &drm_encoder_helper_funcs.dpms
*
* and the CRTC is disabled via one of:
*
* - &drm_crtc_helper_funcs.prepare
* - &drm_crtc_helper_funcs.atomic_disable
* - &drm_crtc_helper_funcs.disable
* - &drm_crtc_helper_funcs.dpms.
*
* The @atomic_disable callback is optional.
*/
void (*atomic_disable)(struct drm_bridge *bridge,
@ -348,16 +447,34 @@ struct drm_bridge_funcs {
/**
* @atomic_post_disable:
*
* This callback should disable the bridge. It is called right after the
* preceding element in the display pipe is disabled. If the preceding
* element is a bridge this means it's called after that bridge's
* @atomic_post_disable or @post_disable function. If the preceding
* element is a &drm_encoder it's called right after the encoder's
* &drm_encoder_helper_funcs.atomic_disable hook.
*
* The bridge must assume that the display pipe (i.e. clocks and timing
* signals) feeding it is no longer running when this callback is
* called.
* signals) feeding this bridge is no longer running when the
* @atomic_post_disable is called.
*
* This callback should perform all the actions required by the hardware
* after it has stopped receiving signals from the preceding element.
*
* If the preceding element is a &drm_bridge, then this is called after
* that bridge is post-disabled (unless marked otherwise by the
* @pre_enable_prev_first flag) via one of:
*
* - &drm_bridge_funcs.post_disable
* - &drm_bridge_funcs.atomic_post_disable
*
* If the preceding element of the bridge is a display controller, then
* this callback is called after the encoder is disabled via one of:
*
* - &drm_encoder_helper_funcs.atomic_disable
* - &drm_encoder_helper_funcs.prepare
* - &drm_encoder_helper_funcs.disable
* - &drm_encoder_helper_funcs.dpms
*
* and the CRTC is disabled via one of:
*
* - &drm_crtc_helper_funcs.prepare
* - &drm_crtc_helper_funcs.atomic_disable
* - &drm_crtc_helper_funcs.disable
* - &drm_crtc_helper_funcs.dpms
*
* The @atomic_post_disable callback is optional.
*/