[Intel-gfx] [PATCH v9 1/2] drm/i915: Introduce async plane update to i915

[Helen Koike]

From: Gustavo Padovan <gustavo.padovan at collabora.com>

Add implementation for async plane update callbacks

Signed-off-by: Gustavo Padovan <gustavo.padovan at collabora.com>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo at collabora.com>
Signed-off-by: Tina Zhang <tina.zhang at intel.com>
Signed-off-by: Helen Koike <helen.koike at collabora.com>
Tested-by: Tina Zhang <tina.zhang at intel.com>

---
Hi,

I tested this patch set with igt (ksm_cursor_legacy and plane_cursor_legacy)
and found no regressions.

This patch depends on [1] "[PATCH] drm: don't block fb changes for async plane updates",
which is already on drm-misc, otherwise there will be a regression on igt tests:

        cursor-vs-flip-atomic-transitions-varying-size
        cursor-vs-flip-toggle
        cursor-vs-flip-varying-size

with errors of type:

"CRITICAL: completed 97 cursor updated in a period of 30 flips, we
expect to complete approximately 15360 updates, with the threshold set
at 7680"

When picking this patch, please backmerge [1] into drm-intel tree.

[1] https://cgit.freedesktop.org/drm/drm-misc/commit/?h=drm-misc-fixes&id=89a4aac0ab0e6f5eea10d7bf4869dd15c3de2cd4

Thanks
Helen

Changes in v9:
 - v8: https://patchwork.kernel.org/patch/10843395/
 - Added tested-by tag
 - submitted to  intel-gfx at lists.freedesktop.org to invoke CI
 - rebased and fixed conflicts on top of drm-tip

Changes in v8:
 - v7: https://lkml.org/lkml/2018/6/8/168
 - v7 was splited in two, one that adds the async callbacks and another
 that updates the cursor.
 - rebase with drm-intel
 - allow async update in all types of planes, not only cursor
 - add watermark checks in async update
 - remove bypass of intel_prepare_plane_fb() in case of async update
 - add missing drm_atomic_helper_cleanup_planes(dev, state) call in
 intel_atomic_commit().
 - use swap() function in async update to set the old_fb in the
 new_state object.
 - use helpers intel_update_plane()/intel_disable_plane()

Changes in v7:
- Rebase on top of drm-intel repository. Hopefully now will play
  nicely with autobuilders.

Changes in v6:
- Rework the intel_plane_atomic_async_update due driver changed from
  last time.
- Removed the mutex_lock/unlock as causes a deadlock.

Changes in v5:
- Call drm_atomic_helper_async_check() from the check hook

Changes in v4:
- Set correct vma to new state for cleanup
- Move size checks back to drivers (Ville Syrjälä)

Changes in v3:
- Move fb setting to core and use new state (Eric Anholt)

 .../gpu/drm/i915/display/intel_atomic_plane.c | 71 +++++++++++++++++++
 drivers/gpu/drm/i915/display/intel_display.c  |  9 +++
 2 files changed, 80 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_atomic_plane.c b/drivers/gpu/drm/i915/display/intel_atomic_plane.c
index 30bd4e76fff9..56881a7ec48e 100644
--- a/drivers/gpu/drm/i915/display/intel_atomic_plane.c
+++ b/drivers/gpu/drm/i915/display/intel_atomic_plane.c
@@ -348,8 +348,79 @@ void i9xx_update_planes_on_crtc(struct intel_atomic_state *state,
 	}
 }
 
+static int intel_plane_atomic_async_check(struct drm_plane *plane,
+					  struct drm_plane_state *state)
+{
+	struct drm_crtc_state *crtc_state;
+
+	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_atomic_state *intel_new_state =
+		to_intel_atomic_state(new_state->state);
+	struct intel_plane *intel_plane = to_intel_plane(plane);
+	struct drm_crtc *crtc = plane->state->crtc;
+	struct intel_crtc_state *new_crtc_state;
+	struct intel_crtc *intel_crtc;
+	int i;
+
+	for_each_new_intel_crtc_in_state(intel_new_state, intel_crtc,
+					 new_crtc_state, i)
+		WARN_ON(new_crtc_state->wm.need_postvbl_update ||
+			new_crtc_state->update_wm_post);
+
+	i915_gem_track_fb(intel_fb_obj(plane->state->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;
+
+	swap(plane->state->fb, new_state->fb);
+
+	if (plane->state->visible)
+		intel_update_plane(intel_plane,
+				   to_intel_crtc_state(crtc->state),
+				   to_intel_plane_state(plane->state));
+	else
+		intel_disable_plane(intel_plane,
+				    to_intel_crtc_state(crtc->state));
+}
+
 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/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index 8d7e4c8b60bc..bf505b70a037 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -14007,6 +14007,15 @@ 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);
+		drm_atomic_helper_cleanup_planes(dev, state);
+		return 0;
+	}
+
 	intel_state->wakeref = intel_runtime_pm_get(&dev_priv->runtime_pm);
 
 	drm_atomic_state_get(state);
-- 
2.20.1