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gamescope: payload 20261103.7, the FPS limiter holds a cap below the panel rate again - #2336

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utkarshdalal merged 1 commit into
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gamescope-payload-20261103-7-cap-gate
Nov 3, 2026
Merged

utkarshdalal merged 1 commit into
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gamescope-payload-20261103-7-cap-gate

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@utkarshdalal

@utkarshdalal utkarshdalal commented Nov 3, 2026 •

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Description

Depends on GameNative/gamenative-drm#49 (open). Do not merge before it.

This ships GameNative/gamenative-drm#49 at 5d1e0ae as gamescope payload 20261103.7. The only change in the app is GamescopePayload.VERSION = 20261103.7. libgamenative_drm.so is unchanged.

What was wrong

On master (payload 20261103.4 to .6) the FPS limiter under gamescope stops holding any cap below the panel's rate once a frame outlasts one vblank. A user set 20 for MGS V: The Phantom Pain on a 120 Hz phone and got 40-50 fps; at 60 Hz the cap held. Reproduced on the Retroid Pocket 6 at 120 Hz with Dave the Diver at 1080p, cap 20: the shim census showed cap=20 gate=vsync with gate_holds frozen and gate_late growing once per frame, at the game's own 53 fps.

Cause: GameNative/gamenative-drm#47 added, next to its fix for the cap-rate FIFO cell (kept), a rule that the release after a late start is never more than one grid instant after it. A cap below the rate holds the guest for a whole slot (six vblanks at 20 on 120 Hz); after that rule fired once, the next release was one vblank away, a frame longer than 8.8 ms was late for it too, and the gate never held again. At 60 Hz only games faster than ~58 fps recovered, which hid it there.

What changes

The shim (gamenative-drm#49): a late start keeps its slot's timeline, so the next release is where the cap puts it; only a start past the whole slot restarts the timeline. The cap-equals-rate cells from #47 and #48 are unchanged (slot and period are equal there).

Measured on the RP6 at 120 Hz, DTD 1080p, limiter switched live

cap before (payload .6) after (this shim)
20 ~53 fps (gate never holds) 20.0 fps, gate_holds +1 per frame
40 — 40.0 fps
60 — 52-53 fps (the game's own rate)

Each switch settled within the same second. A 100 s gameplay run: 2010 frames in 100.4 s = 20.02 fps. Shim unit tests: 90 of 90 on the device.

Payload 20261103.7

gamescope-gamenative-20261103.7.tzst, 14308927 B, sha256 1b2dc7308973d068852a77522206e3472cd89a9c8b2eb5b359954a99c66b4f55, served from both CDN hosts and verified. Same 1014 members as 20261103.6; only lib/libadrenotools_gamescope.so differs (sha256 b10cb50957c1b62b708d42311e49f6972cf154cdaa3fc75d05e6ddbd5f7a9122, build string 2026110317065d1e0ae).

Recording

Census excerpt from the RP6 run at cap 20, before and after, in GameNative/gamenative-drm#49.

Type of Change

  • Bug fix
  • Performance / stability improvement
  • Compatibility improvements
  • Other (requires prior approval)

Checklist

  • If I have access to #code-changes, I have discussed this change there and it has been green-lighted. If I do not have access, I have still provided clear context in this PR. If I skip both, I accept that this change may face delays in review, may not be reviewed at all, or may be closed.
  • This change aligns with the current project scope (core functionality, stability, or performance). If not, it has been explicitly approved beforehand.
  • I have attached a recording of the change.
  • I have read and agree to the contribution guidelines in CONTRIBUTING.md.

Summary by cubic

Ships gamenative-drm#49 as gamescope payload 20261103.7, restoring the FPS limiter so a cap below the panel rate holds again. Only GamescopePayload.VERSION changes.

Bug Fixes

  • On payloads .4–.6, the limit stopped holding once a frame outlasted a vblank (cap 20 on a 120 Hz panel ran at 40–50 fps); a late start now keeps its slot's timeline, so the next release lands where the cap puts it.

Written for commit f58f2ec. Summary will update on new commits.

View guided diff Turn on auto-fix

…panel rate again

Ships GameNative/gamenative-drm#49: the shim's vsync-grid gate no longer
releases the frame after a late start at the next grid instant, a rule
from GameNative/gamenative-drm#47 that made every cap below the panel's
rate stop holding once a frame outlasted one vblank (MGS V at cap 20 on a
120 Hz panel ran at 40-50 fps; DTD at 53). Only GamescopePayload.VERSION
changes.
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coderabbitai Bot commented Nov 3, 2026 •

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@utkarshdalal
utkarshdalal merged commit bac1ba4 into master Nov 3, 2026
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