diff mbox series

[09/65] drm/komeda: Annotate dma-fence critical section in commit path

Message ID 20201023122216.2373294-9-daniel.vetter@ffwll.ch
State New, archived
Headers show
Series [1/3] drm/atomic-helpers: remove legacy_cursor_update hacks | expand

Commit Message

Daniel Vetter Oct. 23, 2020, 12:21 p.m. UTC
Like the helpers, nothing special. Well except not, because we the
critical section extends until after hw_done(), since that's the last
thing which could hold up a subsequent atomic commit. That means the
wait_for_flip_done is included, but that's not a problem, we're
allowed to call dma_fence_wait() from signalling critical sections.
Even on our own fence (which this does), it's just a bit confusing.
But in a way those last 2 function calls are already part of the fence
signalling critical section for the next atomic commit.

Reading this I'm wondering why komeda waits for flip_done() before
calling hw_done(), which is a bit backwards (but hey hw can be
special). Might be good to throw a comment in there that explains why,
because the original commit that added this just doesn't.

Reviewed-by: James Qian Wang <james.qian.wang@arm.com>
Cc: "James (Qian) Wang" <james.qian.wang@arm.com>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Mihail Atanassov <mihail.atanassov@arm.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
 drivers/gpu/drm/arm/display/komeda/komeda_kms.c | 3 +++
 1 file changed, 3 insertions(+)
diff mbox series


diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_kms.c b/drivers/gpu/drm/arm/display/komeda/komeda_kms.c
index 1f6682032ca4..cc5b5915bc5e 100644
--- a/drivers/gpu/drm/arm/display/komeda/komeda_kms.c
+++ b/drivers/gpu/drm/arm/display/komeda/komeda_kms.c
@@ -73,6 +73,7 @@  static struct drm_driver komeda_kms_driver = {
 static void komeda_kms_commit_tail(struct drm_atomic_state *old_state)
 	struct drm_device *dev = old_state->dev;
+	bool fence_cookie = dma_fence_begin_signalling();
 	drm_atomic_helper_commit_modeset_disables(dev, old_state);
@@ -85,6 +86,8 @@  static void komeda_kms_commit_tail(struct drm_atomic_state *old_state)
+	dma_fence_end_signalling(fence_cookie);
 	drm_atomic_helper_cleanup_planes(dev, old_state);