[RFC PATCH 3/7] drm/i915: Introduce async plane update to i915

[Tina Zhang]

This patch is separated from the following patch:
https://lists.freedesktop.org/archives/dri-devel/2018-June/179592.html

This patch introduces the implementation async plane update callbacks
to i915. The original idea is to use async plane update framework to
update cursors.

The next patch of this series try to extend this idea to support other
planes.

Signed-off-by: Tina Zhang <tina.zhang at intel.com>
Cc: Gustavo Padovan <gustavo.padovan at collabora.com>
Cc: Enric Balletbo i Serra <enric.balletbo at collabora.com>
Cc: Helen Koike <helen.koike at collabora.com>
Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/intel_atomic_plane.c | 69 +++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_display.c      | 11 +++++
 2 files changed, 80 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_atomic_plane.c b/drivers/gpu/drm/i915/intel_atomic_plane.c
index 905f8ef..dddd3a7 100644
--- a/drivers/gpu/drm/i915/intel_atomic_plane.c
+++ b/drivers/gpu/drm/i915/intel_atomic_plane.c
@@ -217,10 +217,79 @@ void intel_update_planes_on_crtc(struct intel_atomic_state *old_state,
 	}
 }
 
+static int intel_plane_atomic_async_check(struct drm_plane *plane,
+					  struct drm_plane_state *state)
+{
+	struct drm_crtc_state *crtc_state;
+
+	if (plane->type != DRM_PLANE_TYPE_CURSOR)
+		return -EINVAL;
+
+	crtc_state = drm_atomic_get_existing_crtc_state(state->state,
+							state->crtc);
+	if (WARN_ON(!crtc_state))
+		return -EINVAL;
+
+	/*
+	 * When crtc is inactive or there is a modeset pending,
+	 * wait for it to complete in the slowpath
+	 */
+	if (!crtc_state->active || to_intel_crtc_state(crtc_state)->update_pipe)
+		return -EINVAL;
+
+	/*
+	 * If any parameters change that may affect watermarks,
+	 * take the slowpath. Only changing fb or position should be
+	 * in the fastpath.
+	 */
+	if (plane->state->crtc != state->crtc ||
+	    plane->state->src_w != state->src_w ||
+	    plane->state->src_h != state->src_h ||
+	    plane->state->crtc_w != state->crtc_w ||
+	    plane->state->crtc_h != state->crtc_h ||
+	    !plane->state->fb != !state->fb)
+		return -EINVAL;
+
+	return 0;
+}
+
+static void intel_plane_atomic_async_update(struct drm_plane *plane,
+					    struct drm_plane_state *new_state)
+{
+	struct intel_plane *intel_plane = to_intel_plane(plane);
+	struct drm_crtc *crtc = plane->state->crtc;
+	struct drm_framebuffer *old_fb;
+
+	old_fb = plane->state->fb;
+
+	i915_gem_track_fb(intel_fb_obj(old_fb), intel_fb_obj(new_state->fb),
+			  intel_plane->frontbuffer_bit);
+
+	plane->state->src_x = new_state->src_x;
+	plane->state->src_y = new_state->src_y;
+	plane->state->crtc_x = new_state->crtc_x;
+	plane->state->crtc_y = new_state->crtc_y;
+	plane->state->fb = new_state->fb;
+
+	new_state->fb = old_fb;
+
+	if (plane->state->visible) {
+		trace_intel_update_plane(plane, to_intel_crtc(crtc));
+		intel_plane->update_plane(intel_plane,
+					  to_intel_crtc_state(crtc->state),
+					  to_intel_plane_state(plane->state));
+	} else {
+		trace_intel_disable_plane(plane, to_intel_crtc(crtc));
+		intel_plane->disable_plane(intel_plane, to_intel_crtc(crtc));
+	}
+}
+
 const struct drm_plane_helper_funcs intel_plane_helper_funcs = {
 	.prepare_fb = intel_prepare_plane_fb,
 	.cleanup_fb = intel_cleanup_plane_fb,
 	.atomic_check = intel_plane_atomic_check,
+	.atomic_async_check = intel_plane_atomic_async_check,
+	.atomic_async_update = intel_plane_atomic_async_update,
 };
 
 /**
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 132e978..b64708b 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -13050,6 +13050,14 @@ static int intel_atomic_commit(struct drm_device *dev,
 	struct drm_i915_private *dev_priv = to_i915(dev);
 	int ret = 0;
 
+	if (state->async_update) {
+		ret = drm_atomic_helper_prepare_planes(dev, state);
+		if (ret)
+			return ret;
+		drm_atomic_helper_async_commit(dev, state);
+		return 0;
+	}
+
 	drm_atomic_state_get(state);
 	i915_sw_fence_init(&intel_state->commit_ready,
 			   intel_atomic_commit_ready);
@@ -13275,6 +13283,9 @@ intel_prepare_plane_fb(struct drm_plane *plane,
 	struct drm_i915_gem_object *old_obj = intel_fb_obj(plane->state->fb);
 	int ret;
 
+	if (new_state->state->async_update)
+		return 0;
+
 	if (old_obj) {
 		struct drm_crtc_state *crtc_state =
 			drm_atomic_get_new_crtc_state(new_state->state,
-- 
2.7.4