steamcompmgr: allow uncapped frame rates with adaptive sync#2262
Open
matte-schwartz wants to merge 1 commit into
Open
steamcompmgr: allow uncapped frame rates with adaptive sync#2262matte-schwartz wants to merge 1 commit into
matte-schwartz wants to merge 1 commit into
Conversation
With VRR active, every latched commit is painted immediately and the DRM backend blocks until the flip completes. Faster-than-refresh clients serialize the whole steamcompmgr loop on that wait, capping them at the panel refresh rate even with the FPS limiter disabled. Instead, defer VRR paints until the display can take a new flip, so mailbox/immediate commits keep latching and releasing buffers in between. The readiness check shares the VRR wakeup schedule's lead, a rolling max of wakeup-to-flip-queued time plus the fixed refresh schedule's redzone. Timer vblanks always count as ready, so FIFO clients, the FPS limiter and overlay pacing keep their exact timing. The old behavior is available behind the adaptive_sync_uncapped convar.
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
With VRR active, every latched commit is painted immediately and the DRM backend blocks until the flip completes. Faster-than-refresh clients serialize the whole steamcompmgr loop on that wait, capping them at the panel refresh rate even with the FPS limiter disabled.
Instead, defer VRR paints until the display can take a new flip, so mailbox/immediate commits keep latching and releasing buffers in between.
The readiness check shares the VRR wakeup schedule's lead, a rolling max of wakeup-to-flip-queued time plus the fixed refresh schedule's redzone. Timer vblanks always count as ready, so FIFO clients, the FPS limiter and overlay pacing keep their exact timing. The old behavior is available behind the adaptive_sync_uncapped convar.