drm/atomic: Let drivers decide which planes to async flip

Currently, DRM atomic uAPI allows only primary planes to be flipped
asynchronously. However, each driver might be able to perform async
flips in other different plane types. To enable drivers to set their own
restrictions on which type of plane they can or cannot flip, use the
existing atomic_async_check() from struct drm_plane_helper_funcs to
enhance this flexibility, thus allowing different plane types to be able
to do async flips as well.

Create a new parameter for the atomic_async_check(), `bool flip`. This
parameter is used to distinguish when this function is being called from
a plane update from a full page flip.

In order to prevent regressions and such, we keep the current policy: we
skip the driver check for the primary plane, because it is always
allowed to do async flips on it.

Signed-off-by: André Almeida <andrealmeid@igalia.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Christopher Snowhill <chris@kode54.net>
Tested-by: Christopher Snowhill <chris@kode54.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20250127-tonyk-async_flip-v12-1-0f7f8a8610d3@igalia.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

9 files changed, 42 insertions, 18 deletions

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index d6a206fc9ddd..fd3d14592663 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -1966,7 +1966,7 @@ int drm_atomic_helper_async_check(struct drm_device *dev,
 		return -EBUSY;
 	}
 
-	ret = funcs->atomic_async_check(plane, state);
+	ret = funcs->atomic_async_check(plane, state, false);
 	if (ret != 0)
 		drm_dbg_atomic(dev,
 			       "[PLANE:%d:%s] driver async check failed\n",
diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c
index 370dc676e3aa..2765ba90ad8f 100644
--- a/drivers/gpu/drm/drm_atomic_uapi.c
+++ b/drivers/gpu/drm/drm_atomic_uapi.c
@@ -27,8 +27,9 @@
  * Daniel Vetter <daniel.vetter@ffwll.ch>
  */
 
-#include <drm/drm_atomic_uapi.h>
 #include <drm/drm_atomic.h>
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_atomic_uapi.h>
 #include <drm/drm_framebuffer.h>
 #include <drm/drm_print.h>
 #include <drm/drm_drv.h>
@@ -1063,6 +1064,7 @@ int drm_atomic_set_property(struct drm_atomic_state *state,
 		struct drm_plane *plane = obj_to_plane(obj);
 		struct drm_plane_state *plane_state;
 		struct drm_mode_config *config = &plane->dev->mode_config;
+		const struct drm_plane_helper_funcs *plane_funcs = plane->helper_private;
 
 		plane_state = drm_atomic_get_plane_state(state, plane);
 		if (IS_ERR(plane_state)) {
@@ -1070,15 +1072,30 @@ int drm_atomic_set_property(struct drm_atomic_state *state,
 			break;
 		}
 
-		if (async_flip &&
-		    (plane_state->plane->type != DRM_PLANE_TYPE_PRIMARY ||
-		     (prop != config->prop_fb_id &&
-		      prop != config->prop_in_fence_fd &&
-		      prop != config->prop_fb_damage_clips))) {
-			ret = drm_atomic_plane_get_property(plane, plane_state,
-							    prop, &old_val);
-			ret = drm_atomic_check_prop_changes(ret, old_val, prop_value, prop);
-			break;
+		if (async_flip) {
+			/* check if the prop does a nop change */
+			if ((prop != config->prop_fb_id &&
+			     prop != config->prop_in_fence_fd &&
+			     prop != config->prop_fb_damage_clips)) {
+				ret = drm_atomic_plane_get_property(plane, plane_state,
+								    prop, &old_val);
+				ret = drm_atomic_check_prop_changes(ret, old_val, prop_value, prop);
+			}
+
+			/* ask the driver if this non-primary plane is supported */
+			if (plane->type != DRM_PLANE_TYPE_PRIMARY) {
+				ret = -EINVAL;
+
+				if (plane_funcs && plane_funcs->atomic_async_check)
+					ret = plane_funcs->atomic_async_check(plane, state, true);
+
+				if (ret) {
+					drm_dbg_atomic(prop->dev,
+						       "[PLANE:%d:%s] does not support async flips\n",
+						       obj->id, plane->name);
+					break;
+				}
+			}
 		}
 
 		ret = drm_atomic_plane_set_property(plane,
diff --git a/drivers/gpu/drm/loongson/lsdc_plane.c b/drivers/gpu/drm/loongson/lsdc_plane.c
index d227a2c1dcf1..aa9a97f9c4dc 100644
--- a/drivers/gpu/drm/loongson/lsdc_plane.c
+++ b/drivers/gpu/drm/loongson/lsdc_plane.c
@@ -171,7 +171,8 @@ static const struct drm_plane_helper_funcs lsdc_primary_helper_funcs = {
 };
 
 static int lsdc_cursor_plane_atomic_async_check(struct drm_plane *plane,
-						struct drm_atomic_state *state)
+						struct drm_atomic_state *state,
+						bool flip)
 {
 	struct drm_plane_state *new_state;
 	struct drm_crtc_state *crtc_state;
diff --git a/drivers/gpu/drm/mediatek/mtk_plane.c b/drivers/gpu/drm/mediatek/mtk_plane.c
index 8a48b3b0a956..655106bbb76d 100644
--- a/drivers/gpu/drm/mediatek/mtk_plane.c
+++ b/drivers/gpu/drm/mediatek/mtk_plane.c
@@ -101,7 +101,7 @@ static void mtk_plane_destroy_state(struct drm_plane *plane,
 }
 
 static int mtk_plane_atomic_async_check(struct drm_plane *plane,
-					struct drm_atomic_state *state)
+					struct drm_atomic_state *state, bool flip)
 {
 	struct drm_plane_state *new_plane_state = drm_atomic_get_new_plane_state(state,
 										 plane);
diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c b/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c
index 62de248ed1b0..bb1601921938 100644
--- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c
+++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c
@@ -368,7 +368,7 @@ static void mdp5_plane_atomic_update(struct drm_plane *plane,
 }
 
 static int mdp5_plane_atomic_async_check(struct drm_plane *plane,
-					 struct drm_atomic_state *state)
+					 struct drm_atomic_state *state, bool flip)
 {
 	struct drm_plane_state *new_plane_state = drm_atomic_get_new_plane_state(state,
 										 plane);
diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
index 57747f1cff26..e3596e2b557d 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
@@ -1072,7 +1072,7 @@ static void vop_plane_atomic_update(struct drm_plane *plane,
 }
 
 static int vop_plane_atomic_async_check(struct drm_plane *plane,
-					struct drm_atomic_state *state)
+					struct drm_atomic_state *state, bool flip)
 {
 	struct drm_plane_state *new_plane_state = drm_atomic_get_new_plane_state(state,
 										 plane);
diff --git a/drivers/gpu/drm/tegra/dc.c b/drivers/gpu/drm/tegra/dc.c
index 430b2eededb2..798507a8ae56 100644
--- a/drivers/gpu/drm/tegra/dc.c
+++ b/drivers/gpu/drm/tegra/dc.c
@@ -1025,7 +1025,8 @@ static void tegra_cursor_atomic_disable(struct drm_plane *plane,
 	tegra_dc_writel(dc, value, DC_DISP_DISP_WIN_OPTIONS);
 }
 
-static int tegra_cursor_atomic_async_check(struct drm_plane *plane, struct drm_atomic_state *state)
+static int tegra_cursor_atomic_async_check(struct drm_plane *plane, struct drm_atomic_state *state,
+					   bool flip)
 {
 	struct drm_plane_state *new_state = drm_atomic_get_new_plane_state(state, plane);
 	struct drm_crtc_state *crtc_state;
diff --git a/drivers/gpu/drm/vc4/vc4_plane.c b/drivers/gpu/drm/vc4/vc4_plane.c
index d608860d525f..c5e84d3494d2 100644
--- a/drivers/gpu/drm/vc4/vc4_plane.c
+++ b/drivers/gpu/drm/vc4/vc4_plane.c
@@ -2338,7 +2338,7 @@ static void vc4_plane_atomic_async_update(struct drm_plane *plane,
 }
 
 static int vc4_plane_atomic_async_check(struct drm_plane *plane,
-					struct drm_atomic_state *state)
+					struct drm_atomic_state *state, bool flip)
 {
 	struct vc4_dev *vc4 = to_vc4_dev(plane->dev);
 	struct drm_plane_state *new_plane_state = drm_atomic_get_new_plane_state(state,
diff --git a/include/drm/drm_modeset_helper_vtables.h b/include/drm/drm_modeset_helper_vtables.h
index b62f41f48962..ce7c7aeac887 100644
--- a/include/drm/drm_modeset_helper_vtables.h
+++ b/include/drm/drm_modeset_helper_vtables.h
@@ -1400,13 +1400,18 @@ struct drm_plane_helper_funcs {
 	 * given update can be committed asynchronously, that is, if it can
 	 * jump ahead of the state currently queued for update.
 	 *
+	 * This function is also used by drm_atomic_set_property() to determine
+	 * if the plane can be flipped in async. The flip flag is used to
+	 * distinguish if the function is used for just the plane state or for a
+	 * flip.
+	 *
 	 * RETURNS:
 	 *
 	 * Return 0 on success and any error returned indicates that the update
 	 * can not be applied in asynchronous manner.
 	 */
 	int (*atomic_async_check)(struct drm_plane *plane,
-				  struct drm_atomic_state *state);
+				  struct drm_atomic_state *state, bool flip);
 
 	/**
 	 * @atomic_async_update: