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

Maxime Ripard
2020-12-04T15:14:03Z

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;