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vblankmanager: keep the fixed-refresh wakeup after the previous vblank - #2528
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matte-schwartz merged 1 commit intoOct 31, 2026
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From about 240 Hz up, the compositing floor plus the redzone fills the whole refresh, so the wakeup lands on the vblank that anchors it. On an RTX 5090 that commit completes off the refresh grid and the schedule slips, about 114 flips a second at a pinned 120 Hz. Cap the lead so the wakeup falls at least a redzone after the anchoring vblank, or half a refresh when the redzone is longer. The 5090 needs about 30% of a refresh of room to stay on the grid. Below 300 Hz this costs at most one redzone, and only when the lead nearly fills the refresh. Closes: ValveSoftware#2527
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From about 240 Hz up, the compositing floor plus the redzone fills the whole refresh, so the wakeup lands on the vblank that anchors it. On an RTX 5090 that commit completes off the refresh grid and the schedule slips, about 114 flips a second at a pinned 120 Hz, in line with #2527.
Cap the lead so the wakeup falls at least a redzone after the anchoring vblank, or half a refresh when the redzone is longer. The 5090 needs about 30% of a refresh of room to stay on the grid. Below 300 Hz this costs at most one redzone, and only when the lead nearly fills the refresh.