Re: [PATCH 2/6] drm: Add drm_atomic_helper_buffer_damage_{iter_init, merged}() helpers

Hi

Am 09.11.23 um 18:24 schrieb Javier Martinez Canillas:

To be used by drivers that do per-buffer (e.g: virtio-gpu) uploads (rather than per-plane uploads), since these type of drivers need to handle buffer damages instead of frame damages.

The drm_atomic_helper_buffer_damage_iter_init() has the same logic than drm_atomic_helper_damage_iter_init() but it also takes into account if the framebuffer attached to plane's state has changed since the last update.

And the drm_atomic_helper_buffer_damage_merged() is just a version of the drm_atomic_helper_damage_merged() helper, but it uses the iter_init helper that is mentioned above.

Fixes: 01f05940a9a7 ("drm/virtio: Enable fb damage clips property for the primary plane") Cc: stable@vger.kernel.org # v6.4+ Reported-by: nerdopolis bluescreen_avenger@verizon.net Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218115 Suggested-by: Sima Vetter daniel.vetter@ffwll.ch Signed-off-by: Javier Martinez Canillas javierm@redhat.com

---

drivers/gpu/drm/drm_damage_helper.c | 79 ++++++++++++++++++++++++++--- include/drm/drm_damage_helper.h | 7 +++ 2 files changed, 80 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/drm_damage_helper.c b/drivers/gpu/drm/drm_damage_helper.c index aa2325567918..b72062c9d31c 100644 --- a/drivers/gpu/drm/drm_damage_helper.c +++ b/drivers/gpu/drm/drm_damage_helper.c @@ -204,7 +204,8 @@ EXPORT_SYMBOL(drm_atomic_helper_dirtyfb); static void __drm_atomic_helper_damage_iter_init(struct drm_atomic_helper_damage_iter *iter, const struct drm_plane_state *old_state,

• 		     const struct drm_plane_state *state)
  

• 		     const struct drm_plane_state *state,
  

• 		     bool buffer_damage)
  

  { struct drm_rect src; memset(iter, 0, sizeof(*iter));

@@ -223,7 +224,8 @@ __drm_atomic_helper_damage_iter_init(struct drm_atomic_helper_damage_iter *iter, iter->plane_src.x2 = (src.x2 >> 16) + !!(src.x2 & 0xFFFF); iter->plane_src.y2 = (src.y2 >> 16) + !!(src.y2 & 0xFFFF);

• if (!iter->clips || !drm_rect_equals(&state->src, &old_state->src)) {

• if (!iter->clips || !drm_rect_equals(&state->src, &old_state->src) ||

•    (buffer_damage && old_state->fb != state->fb)) {
  

I'd assume that this change effectivly disables damage handling. AFAICT user space often does a page flip with a new framebuffer plus damage data. Now, with each change of the framebuffer we ignore the damage information. It's not a blocker as that's the behavior before 6.4, but we should be aware of it.

Best regards Thomas

iter->clips = NULL;
iter->num_clips = 0;
iter->full_update = true;

@@ -243,6 +245,10 @@ __drm_atomic_helper_damage_iter_init(struct drm_atomic_helper_damage_iter *iter,

• update). Currently this iterator returns full plane src in case plane src
• changed but that can be changed in future to return damage.

• • Note that this helper is for drivers that do per-plane uploads and expect
• • to handle frame damages. Drivers that do per-buffer uploads instead should
• • use @drm_atomic_helper_buffer_damage_iter_init() that handles buffer damages.
• • For the case when plane is not visible or plane update should not happen the
  • first call to iter_next will return false. Note that this helper use clipped
  • &drm_plane_state.src, so driver calling this helper should have called

@@ -253,10 +259,37 @@ drm_atomic_helper_damage_iter_init(struct drm_atomic_helper_damage_iter *iter, const struct drm_plane_state *old_state, const struct drm_plane_state *state) {

• __drm_atomic_helper_damage_iter_init(iter, old_state, state);

• __drm_atomic_helper_damage_iter_init(iter, old_state, state, false); } EXPORT_SYMBOL(drm_atomic_helper_damage_iter_init);

+/**

• • drm_atomic_helper_buffer_damage_iter_init - Initialize the buffer damage iterator.
• • @iter: The iterator to initialize.
• • @old_state: Old plane state for validation.
• • @state: Plane state from which to iterate the damage clips.
• • Initialize an iterator, which clips buffer damage
• • &drm_plane_state.fb_damage_clips to plane &drm_plane_state.src. This iterator
• • returns full plane src in case buffer damage is not present because user-space
• • didn't sent, driver discarded it (it want to do full plane update) or the plane
• • @state has an attached framebuffer that is different than the one in @state (it
• • has changed since the last plane update).
• • For the case when plane is not visible or plane update should not happen the
• • first call to iter_next will return false. Note that this helper use clipped
• • &drm_plane_state.src, so driver calling this helper should have called
• • drm_atomic_helper_check_plane_state() earlier.
• */

+void +drm_atomic_helper_buffer_damage_iter_init(struct drm_atomic_helper_damage_iter *iter,

• 			  const struct drm_plane_state *old_state,
  

• 			  const struct drm_plane_state *state)
  

+{

• __drm_atomic_helper_damage_iter_init(iter, old_state, state, true);

+} +EXPORT_SYMBOL(drm_atomic_helper_buffer_damage_iter_init);

• /**
  • drm_atomic_helper_damage_iter_next - Advance the damage iterator.
  • @iter: The iterator to advance.

@@ -301,7 +334,8 @@ EXPORT_SYMBOL(drm_atomic_helper_damage_iter_next); static bool __drm_atomic_helper_damage_merged(const struct drm_plane_state *old_state, struct drm_plane_state *state,

• 			      struct drm_rect *rect)
  

• 			      struct drm_rect *rect,
  

• 			      bool buffer_damage)
  

  { struct drm_atomic_helper_damage_iter iter; struct drm_rect clip;

@@ -312,7 +346,7 @@ static bool __drm_atomic_helper_damage_merged(const struct drm_plane_state *old_ rect->x2 = 0; rect->y2 = 0;

• drm_atomic_helper_damage_iter_init(&iter, old_state, state);

• __drm_atomic_helper_damage_iter_init(&iter, old_state, state, buffer_damage); drm_atomic_for_each_plane_damage(&iter, &clip) { rect->x1 = min(rect->x1, clip.x1); rect->y1 = min(rect->y1, clip.y1);

@@ -336,6 +370,10 @@ static bool __drm_atomic_helper_damage_merged(const struct drm_plane_state *old_

• For details see: drm_atomic_helper_damage_iter_init() and
• drm_atomic_helper_damage_iter_next().

• • Note that this helper is for drivers that do per-plane uploads and expect
• • to handle frame damages. Drivers that do per-buffer uploads instead should
• • use @drm_atomic_helper_buffer_damage_merged() that handles buffer damages.
• • Returns:
  • True if there is valid plane damage otherwise false.
  */

@@ -343,6 +381,35 @@ bool drm_atomic_helper_damage_merged(const struct drm_plane_state *old_state, struct drm_plane_state *state, struct drm_rect *rect) {

• return __drm_atomic_helper_damage_merged(old_state, state, rect);

• return __drm_atomic_helper_damage_merged(old_state, state, rect, false); } EXPORT_SYMBOL(drm_atomic_helper_damage_merged);

+/**

• • drm_atomic_helper_buffer_damage_merged - Merged buffer damage
• • @old_state: Old plane state for validation.
• • @state: Plane state from which to iterate the damage clips.
• • @rect: Returns the merged buffer damage rectangle
• • This function merges any valid buffer damage clips into one rectangle and
• • returns it in @rect. It checks if the framebuffers attached to @old_state
• • and @state are the same. If that is not the case then the returned damage
• • rectangle is the &drm_plane_state.src, since a full update should happen.
• • Note that &drm_plane_state.fb_damage_clips == NULL in plane state means that
• • full plane update should happen. It also ensure helper iterator will return
• • &drm_plane_state.src as damage.
• • For details see: drm_atomic_helper_buffer_damage_iter_init() and
• • drm_atomic_helper_damage_iter_next().
• • Returns:
• • True if there is valid buffer damage otherwise false.
• */

+bool drm_atomic_helper_buffer_damage_merged(const struct drm_plane_state *old_state,

• 			    struct drm_plane_state *state,
  

• 			    struct drm_rect *rect)
  

+{

• return __drm_atomic_helper_damage_merged(old_state, state, rect, true);

+} +EXPORT_SYMBOL(drm_atomic_helper_buffer_damage_merged); diff --git a/include/drm/drm_damage_helper.h b/include/drm/drm_damage_helper.h index effda42cce31..328bb249d68f 100644 --- a/include/drm/drm_damage_helper.h +++ b/include/drm/drm_damage_helper.h @@ -74,11 +74,18 @@ void drm_atomic_helper_damage_iter_init(struct drm_atomic_helper_damage_iter *iter, const struct drm_plane_state *old_state, const struct drm_plane_state *new_state); +void +drm_atomic_helper_buffer_damage_iter_init(struct drm_atomic_helper_damage_iter *iter,

• 			  const struct drm_plane_state *old_state,
  

• 			  const struct drm_plane_state *new_state);
  

  bool drm_atomic_helper_damage_iter_next(struct drm_atomic_helper_damage_iter *iter, struct drm_rect *rect); bool drm_atomic_helper_damage_merged(const struct drm_plane_state *old_state, struct drm_plane_state *state, struct drm_rect *rect);

+bool drm_atomic_helper_buffer_damage_merged(const struct drm_plane_state *old_state,

• 			    struct drm_plane_state *state,
  

• 			    struct drm_rect *rect);
  

#endif