[PATCH v2 6/7] drm/vc4: kms: Remove async modeset semaphore

[Maxime Ripard <maxime@cerno.tech>]

Now that we have proper ordering guaranteed by the previous patch, the
semaphore is redundant and can be removed.

Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
---
 drivers/gpu/drm/vc4/vc4_crtc.c | 13 -------------
 drivers/gpu/drm/vc4/vc4_drv.h  |  2 --
 drivers/gpu/drm/vc4/vc4_kms.c  | 24 ++----------------------
 3 files changed, 2 insertions(+), 37 deletions(-)

diff --git a/drivers/gpu/drm/vc4/vc4_crtc.c b/drivers/gpu/drm/vc4/vc4_crtc.c
index 482219fb4db2..c469594a2d3a 100644
--- a/drivers/gpu/drm/vc4/vc4_crtc.c
+++ b/drivers/gpu/drm/vc4/vc4_crtc.c
@@ -690,7 +690,6 @@ vc4_async_page_flip_complete(struct vc4_seqno_cb *cb)
 		container_of(cb, struct vc4_async_flip_state, cb);
 	struct drm_crtc *crtc = flip_state->crtc;
 	struct drm_device *dev = crtc->dev;
-	struct vc4_dev *vc4 = to_vc4_dev(dev);
 	struct drm_plane *plane = crtc->primary;
 
 	vc4_plane_async_set_fb(plane, flip_state->fb);
@@ -722,8 +721,6 @@ vc4_async_page_flip_complete(struct vc4_seqno_cb *cb)
 	}
 
 	kfree(flip_state);
-
-	up(&vc4->async_modeset);
 }
 
 /* Implements async (non-vblank-synced) page flips.
@@ -738,7 +735,6 @@ static int vc4_async_page_flip(struct drm_crtc *crtc,
 			       uint32_t flags)
 {
 	struct drm_device *dev = crtc->dev;
-	struct vc4_dev *vc4 = to_vc4_dev(dev);
 	struct drm_plane *plane = crtc->primary;
 	int ret = 0;
 	struct vc4_async_flip_state *flip_state;
@@ -767,15 +763,6 @@ static int vc4_async_page_flip(struct drm_crtc *crtc,
 	flip_state->crtc = crtc;
 	flip_state->event = event;
 
-	/* Make sure all other async modesetes have landed. */
-	ret = down_interruptible(&vc4->async_modeset);
-	if (ret) {
-		drm_framebuffer_put(fb);
-		vc4_bo_dec_usecnt(bo);
-		kfree(flip_state);
-		return ret;
-	}
-
 	/* Save the current FB before it's replaced by the new one in
 	 * drm_atomic_set_fb_for_plane(). We'll need the old FB in
 	 * vc4_async_page_flip_complete() to decrement the BO usecnt and keep
diff --git a/drivers/gpu/drm/vc4/vc4_drv.h b/drivers/gpu/drm/vc4/vc4_drv.h
index c5f2944d5bc6..4dcef3140dff 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.h
+++ b/drivers/gpu/drm/vc4/vc4_drv.h
@@ -215,8 +215,6 @@ struct vc4_dev {
 		struct work_struct reset_work;
 	} hangcheck;
 
-	struct semaphore async_modeset;
-
 	struct drm_modeset_lock ctm_state_lock;
 	struct drm_private_obj ctm_manager;
 	struct drm_private_obj hvs_channels;
diff --git a/drivers/gpu/drm/vc4/vc4_kms.c b/drivers/gpu/drm/vc4/vc4_kms.c
index fa40c44eb770..ffbfdde55fff 100644
--- a/drivers/gpu/drm/vc4/vc4_kms.c
+++ b/drivers/gpu/drm/vc4/vc4_kms.c
@@ -418,8 +418,6 @@ vc4_atomic_complete_commit(struct drm_atomic_state *state)
 		clk_set_min_rate(hvs->core_clk, 0);
 
 	drm_atomic_state_put(state);
-
-	up(&vc4->async_modeset);
 }
 
 static void commit_work(struct work_struct *work)
@@ -477,26 +475,17 @@ static int vc4_atomic_commit(struct drm_device *dev,
 			     struct drm_atomic_state *state,
 			     bool nonblock)
 {
-	struct vc4_dev *vc4 = to_vc4_dev(dev);
 	int ret;
 
 	if (state->async_update) {
-		ret = down_interruptible(&vc4->async_modeset);
-		if (ret)
-			return ret;
-
 		ret = drm_atomic_helper_prepare_planes(dev, state);
-		if (ret) {
-			up(&vc4->async_modeset);
+		if (ret)
 			return ret;
-		}
 
 		drm_atomic_helper_async_commit(dev, state);
 
 		drm_atomic_helper_cleanup_planes(dev, state);
 
-		up(&vc4->async_modeset);
-
 		return 0;
 	}
 
@@ -512,21 +501,14 @@ static int vc4_atomic_commit(struct drm_device *dev,
 
 	INIT_WORK(&state->commit_work, commit_work);
 
-	ret = down_interruptible(&vc4->async_modeset);
-	if (ret)
-		return ret;
-
 	ret = drm_atomic_helper_prepare_planes(dev, state);
-	if (ret) {
-		up(&vc4->async_modeset);
+	if (ret)
 		return ret;
-	}
 
 	if (!nonblock) {
 		ret = drm_atomic_helper_wait_for_fences(dev, state, true);
 		if (ret) {
 			drm_atomic_helper_cleanup_planes(dev, state);
-			up(&vc4->async_modeset);
 			return ret;
 		}
 	}
@@ -1008,8 +990,6 @@ int vc4_kms_load(struct drm_device *dev)
 		vc4->load_tracker_enabled = true;
 	}
 
-	sema_init(&vc4->async_modeset, 1);
-
 	/* Set support for vblank irq fast disable, before drm_vblank_init() */
 	dev->vblank_disable_immediate = true;
 
-- 
2.28.0