forked from unom/punktfunk
enricobuehlerandClaude Opus 5
e08474d96d
"AMD's Windows driver offers no MAILBOX" is the premise the FIFO glass gate is built on, and it has been carried in a code comment rather than measured. Present modes are a property of the (surface, device) pair — they vary by platform surface, driver version and fullscreen state — so the only way to settle it is to read them back from real machines. One unconditional log line makes every field log answer the question. First reading, .21 (NVIDIA 610.43.03, GNOME/Wayland): surface present modes available=[MAILBOX, 1000361000, FIFO] Two things fall out. No IMMEDIATE and no FIFO_RELAXED on this surface, which is why a PUNKTFUNK_PRESENT_MODE=immediate run reported mode=fifo — the pin was not offered and the ladder fell through; previously that looked like a puzzling result and is now evidence. And 1000361000 is VK_PRESENT_MODE_FIFO_LATEST_READY_EXT: FIFO's tear-free vblank pacing that presents the LATEST READY image instead of draining a queue — the driver-native version of what the glass gate emulates in software, and a candidate to replace it wherever the driver exposes it (needs VK_EXT_present_mode_fifo_latest_ready enabled at device creation, so a work package rather than a tweak). Also documents PUNKTFUNK_VRR_FIFO, which the previous commit introduced without a docs entry. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>