[PATCH 7/8] drm/vc4: kms: Remove async modeset semaphore

From: Maxime Ripard <maxime@cerno.tech>
To: Mark Rutland <mark.rutland@arm.com>,
	Rob Herring <robh+dt@kernel.org>,
	Frank Rowand <frowand.list@gmail.com>,
	Eric Anholt <eric@anholt.net>,
	Daniel Vetter <daniel.vetter@intel.com>,
	David Airlie <airlied@linux.ie>,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Thomas Zimmermann <tzimmermann@suse.de>,
	Maxime Ripard <maxime@cerno.tech>
Cc: devicetree@vger.kernel.org, Tim Gover <tim.gover@raspberrypi.com>,
	Dave Stevenson <dave.stevenson@raspberrypi.com>,
	dri-devel@lists.freedesktop.org,
	bcm-kernel-feedback-list@broadcom.com,
	linux-rpi-kernel@lists.infradead.org,
	Phil Elwell <phil@raspberrypi.com>,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH 7/8] drm/vc4: kms: Remove async modeset semaphore
Date: Fri, 13 Nov 2020 16:29:55 +0100	[thread overview]
Message-ID: <20201113152956.139663-8-maxime@cerno.tech> (raw)
In-Reply-To: <20201113152956.139663-1-maxime@cerno.tech>

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

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  | 20 +-------------------
 3 files changed, 1 insertion(+), 34 deletions(-)

diff --git a/drivers/gpu/drm/vc4/vc4_crtc.c b/drivers/gpu/drm/vc4/vc4_crtc.c
index 29b77f4b4e56..65d43e2e1d51 100644
--- a/drivers/gpu/drm/vc4/vc4_crtc.c
+++ b/drivers/gpu/drm/vc4/vc4_crtc.c
@@ -699,7 +699,6 @@ 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);
@@ -731,8 +730,6 @@ vc4_async_page_flip_complete(struct vc4_seqno_cb *cb)
 	}
 
 	kfree(flip_state);
-
-	up(&vc4->async_modeset);
 }
 
 /* Implements async (non-vblank-synced) page flips.
@@ -747,7 +744,6 @@ 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;
@@ -776,15 +772,6 @@ 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 9eefd76cb09e..60062afba7b6 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 849bc6b4cea4..79ab7b8a5e0e 100644
--- a/drivers/gpu/drm/vc4/vc4_kms.c
+++ b/drivers/gpu/drm/vc4/vc4_kms.c
@@ -414,8 +414,6 @@ 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)
@@ -473,14 +471,9 @@ 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);
@@ -491,8 +484,6 @@ static int vc4_atomic_commit(struct drm_device *dev,
 
 		drm_atomic_helper_cleanup_planes(dev, state);
 
-		up(&vc4->async_modeset);
-
 		return 0;
 	}
 
@@ -508,21 +499,14 @@ 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;
 		}
 	}
@@ -1006,8 +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

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