[Intel-gfx] [PATCH] drm/i915: Unset legacy_cursor_update early in intel_atomic_commit

[Maarten Lankhorst]

Commit b44d5c0c105a ("drm/i915: Always wait for flip_done, v2.") removed
the call to wait_for_vblanks and replaced it with flip_done.

Unfortunately legacy_cursor_update was unset too late, and the
replacement call drm_atomic_helper_wait_for_flip_done() was
a noop. Make sure that its unset before setup_commit() is
called to fix this issue.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Fixes: b44d5c0c105a ("drm/i915: Always wait for flip_done, v2.")
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=102675
Testcase: kms_cursor_crc
Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
Cc: Jani Nikula <jani.nikula at linux.intel.com>
Reported-by: Marta Löfstedt <marta.lofstedt at intel.com>
Cc: Marta Löfstedt <marta.lofstedt at intel.com>
---
 drivers/gpu/drm/i915/intel_display.c | 44 ++++++++++++++++++++----------------
 1 file changed, 24 insertions(+), 20 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index ba76b2db939c..c1da48d77c8e 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -12412,23 +12412,14 @@ static int intel_atomic_commit(struct drm_device *dev,
 {
 	struct intel_atomic_state *intel_state = to_intel_atomic_state(state);
 	struct drm_i915_private *dev_priv = to_i915(dev);
-	int ret = 0;
-
-	ret = drm_atomic_helper_setup_commit(state, nonblock);
-	if (ret)
-		return ret;
+	struct drm_crtc_state *new_crtc_state;
+	struct drm_crtc *crtc;
+	int i, ret = 0;
 
 	drm_atomic_state_get(state);
 	i915_sw_fence_init(&intel_state->commit_ready,
 			   intel_atomic_commit_ready);
 
-	ret = intel_atomic_prepare_commit(dev, state);
-	if (ret) {
-		DRM_DEBUG_ATOMIC("Preparing state failed with %i\n", ret);
-		i915_sw_fence_commit(&intel_state->commit_ready);
-		return ret;
-	}
-
 	/*
 	 * The intel_legacy_cursor_update() fast path takes care
 	 * of avoiding the vblank waits for simple cursor
@@ -12437,19 +12428,32 @@ static int intel_atomic_commit(struct drm_device *dev,
 	 * updates happen during the correct frames. Gen9+ have
 	 * double buffered watermarks and so shouldn't need this.
 	 *
-	 * Do this after drm_atomic_helper_setup_commit() and
-	 * intel_atomic_prepare_commit() because we still want
-	 * to skip the flip and fb cleanup waits. Although that
-	 * does risk yanking the mapping from under the display
-	 * engine.
+	 * Unset state->legacy_cursor_update before the call to
+	 * drm_atomic_helper_setup_commit() because otherwise
+	 * drm_atomic_helper_wait_for_flip_done() is a noop and
+	 * we get FIFO underruns because we didn't wait
+	 * for vblank.
 	 *
 	 * FIXME doing watermarks and fb cleanup from a vblank worker
 	 * (assuming we had any) would solve these problems.
 	 */
-	if (INTEL_GEN(dev_priv) < 9)
-		state->legacy_cursor_update = false;
+	if (INTEL_GEN(dev_priv) < 9 && state->legacy_cursor_update) {
+		for_each_new_crtc_in_state(state, crtc, new_crtc_state, i)
+			if (to_intel_crtc_state(new_crtc_state)->wm.need_postvbl_update)
+				state->legacy_cursor_update = false;
+	}
+
+	ret = intel_atomic_prepare_commit(dev, state);
+	if (ret) {
+		DRM_DEBUG_ATOMIC("Preparing state failed with %i\n", ret);
+		i915_sw_fence_commit(&intel_state->commit_ready);
+		return ret;
+	}
+
+	ret = drm_atomic_helper_setup_commit(state, nonblock);
+	if (!ret)
+		ret = drm_atomic_helper_swap_state(state, true);
 
-	ret = drm_atomic_helper_swap_state(state, true);
 	if (ret) {
 		i915_sw_fence_commit(&intel_state->commit_ready);
 
-- 
2.14.1