[Intel-gfx] [PATCH 2/4] drm/i915: Check async flip capability early on

[Ville Syrjala]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

Since the async flip state check is done very late and
thus it can see potentially all the planes in the state
(due to the wm/ddb optimization) we need to move the
"can the requested plane do async flips at all?" check
much earlier. For this purpose we introduce
intel_async_flip_check_uapi() that gets called early during
the atomic check.

And for good measure we'll throw in a couple of basic checks:
- is the crtc active?
- was a modeset flagged?
- is+was the plane enabled?
Though atm all of those should be guaranteed by the fact
that the async flip can only be requested through the legacy
page flip ioctl.

Cc: Stanislav Lisovskiy <stanislav.lisovskiy at intel.com>
Fixes: c3639f3be480 ("drm/i915: Use wm0 only during async flips for DG2")
Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/display/intel_display.c | 79 ++++++++++++++++++--
 1 file changed, 72 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index baa291e4943f..5a8c7816d29e 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -7463,7 +7463,7 @@ static void kill_bigjoiner_slave(struct intel_atomic_state *state,
  * Correspondingly, support is currently added for primary plane only.
  *
  * Async flip can only change the plane surface address, so anything else
- * changing is rejected from the intel_atomic_check_async() function.
+ * changing is rejected from the intel_async_flip_check_hw() function.
  * Once this check is cleared, flip done interrupt is enabled using
  * the intel_crtc_enable_flip_done() function.
  *
@@ -7473,7 +7473,65 @@ static void kill_bigjoiner_slave(struct intel_atomic_state *state,
  * correspond to the last vblank and have no relation to the actual time when
  * the flip done event was sent.
  */
-static int intel_atomic_check_async(struct intel_atomic_state *state, struct intel_crtc *crtc)
+static int intel_async_flip_check_uapi(struct intel_atomic_state *state,
+				       struct intel_crtc *crtc)
+{
+	struct drm_i915_private *i915 = to_i915(state->base.dev);
+	const struct intel_crtc_state *new_crtc_state =
+		intel_atomic_get_new_crtc_state(state, crtc);
+	const struct intel_plane_state *old_plane_state;
+	struct intel_plane_state *new_plane_state;
+	struct intel_plane *plane;
+	int i;
+
+	if (!new_crtc_state->uapi.async_flip)
+		return 0;
+
+	if (!new_crtc_state->uapi.active) {
+		drm_dbg_kms(&i915->drm,
+			    "[CRTC:%d:%s] not active\n",
+			    crtc->base.base.id, crtc->base.name);
+		return -EINVAL;
+	}
+
+	if (intel_crtc_needs_modeset(new_crtc_state)) {
+		drm_dbg_kms(&i915->drm,
+			    "[CRTC:%d:%s] modeset required\n",
+			    crtc->base.base.id, crtc->base.name);
+		return -EINVAL;
+	}
+
+	for_each_oldnew_intel_plane_in_state(state, plane, old_plane_state,
+					     new_plane_state, i) {
+		if (plane->pipe != crtc->pipe)
+			continue;
+
+		/*
+		 * TODO: Async flip is only supported through the page flip IOCTL
+		 * as of now. So support currently added for primary plane only.
+		 * Support for other planes on platforms on which supports
+		 * this(vlv/chv and icl+) should be added when async flip is
+		 * enabled in the atomic IOCTL path.
+		 */
+		if (!plane->async_flip) {
+			drm_dbg_kms(&i915->drm,
+				    "[PLANE:%d:%s] async flip not supported\n",
+				    plane->base.base.id, plane->base.name);
+			return -EINVAL;
+		}
+
+		if (!old_plane_state->uapi.fb || !new_plane_state->uapi.fb) {
+			drm_dbg_kms(&i915->drm,
+				    "[PLANE:%d:%s] no old or new framebuffer\n",
+				    plane->base.base.id, plane->base.name);
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+static int intel_async_flip_check_hw(struct intel_atomic_state *state, struct intel_crtc *crtc)
 {
 	struct drm_i915_private *i915 = to_i915(state->base.dev);
 	const struct intel_crtc_state *old_crtc_state, *new_crtc_state;
@@ -7484,6 +7542,9 @@ static int intel_atomic_check_async(struct intel_atomic_state *state, struct int
 	old_crtc_state = intel_atomic_get_old_crtc_state(state, crtc);
 	new_crtc_state = intel_atomic_get_new_crtc_state(state, crtc);
 
+	if (!new_crtc_state->uapi.async_flip)
+		return 0;
+
 	if (intel_crtc_needs_modeset(new_crtc_state)) {
 		drm_dbg_kms(&i915->drm, "Modeset Required. Async flip not supported\n");
 		return -EINVAL;
@@ -7675,6 +7736,12 @@ static int intel_atomic_check(struct drm_device *dev,
 	if (ret)
 		goto fail;
 
+	for_each_new_intel_crtc_in_state(state, crtc, new_crtc_state, i) {
+		ret = intel_async_flip_check_uapi(state, crtc);
+		if (ret)
+			return ret;
+	}
+
 	ret = intel_bigjoiner_add_affected_crtcs(state);
 	if (ret)
 		goto fail;
@@ -7834,11 +7901,9 @@ static int intel_atomic_check(struct drm_device *dev,
 
 	for_each_oldnew_intel_crtc_in_state(state, crtc, old_crtc_state,
 					    new_crtc_state, i) {
-		if (new_crtc_state->uapi.async_flip) {
-			ret = intel_atomic_check_async(state, crtc);
-			if (ret)
-				goto fail;
-		}
+		ret = intel_async_flip_check_hw(state, crtc);
+		if (ret)
+			goto fail;
 
 		if (!intel_crtc_needs_modeset(new_crtc_state) &&
 		    !new_crtc_state->update_pipe)
-- 
2.34.1