[PATCH v3 2/2] drm/vc4: Set ->legacy_cursor_update to false when doing non-async updates

[Boris Brezillon]

drm_atomic_helper_setup_commit() auto-completes commit->flip_done when
state->legacy_cursor_update is true, but we know for sure that we want
a sync update when we call drm_atomic_helper_setup_commit() from
vc4_atomic_commit().

Explicitly set state->legacy_cursor_update to false to prevent this
auto-completion.

Fixes: 184d3cf4f738 ("drm/vc4: Use wait_for_flip_done() instead of wait_for_vblanks()")
Cc: <stable at vger.kernel.org>
Signed-off-by: Boris Brezillon <boris.brezillon at bootlin.com>
Reviewed-by: Eric Anholt <eric at anholt.net>
---
Changes in v3:
- Add missing Fixes and Cc-stable tags
- Fix a typo in the commit message

Changes in v2:
- Add Eric's R-b
---
 drivers/gpu/drm/vc4/vc4_kms.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/vc4/vc4_kms.c b/drivers/gpu/drm/vc4/vc4_kms.c
index 127468785f74..1f94b9affe4b 100644
--- a/drivers/gpu/drm/vc4/vc4_kms.c
+++ b/drivers/gpu/drm/vc4/vc4_kms.c
@@ -214,6 +214,12 @@ static int vc4_atomic_commit(struct drm_device *dev,
 		return 0;
 	}
 
+	/* We know for sure we don't want an async update here. Set
+	 * state->legacy_cursor_update to false to prevent
+	 * drm_atomic_helper_setup_commit() from auto-completing
+	 * commit->flip_done.
+	 */
+	state->legacy_cursor_update = false;
 	ret = drm_atomic_helper_setup_commit(state, nonblock);
 	if (ret)
 		return ret;
-- 
2.17.1