feat(videoout): expose buffer labels and release replaced frames

[JJenkx]

What

Implement sceVideoOutGetBufferLabelAddress with a port-owned array of 16 aligned 64-bit labels. Return its address and count, reset newly registered slots, and release the previous displayed buffer's label when its replacement completes presentation. Black/blank replacements release the previous buffer without using a negative index. Ports and reopened generations have separate arrays.

Route stores through a graphics-driver helper retained by production NID patching, so the memory tracker observes an atomic release store. Failed handle/pointer queries preserve output, and successful pointer output supports unaligned storage.

Astro Bot PPSA21564's bundled driver uses a pointer output and base + index * 8. Count and release behavior follow shadPS4 and its driver. PS5 timing, error policy, repeated same-buffer flips and concurrent guest stores remain unverified and documented in library debt. This does not implement EOP-flip tokens, which are separate work in #5539.

Tested

• Full standalone Linux/Windows fork CI passes published head d1de55fb3306, containing main d1670009fbfd: Linux 1,037 passed / 48 skipped; Windows 714 passed / 391 skipped. Display-dependent label cases are skipped on these runners and remain outside CI's functional validation.
• Local native X11 tests on Radeon and lavapipe cover count/width/alignment, unaligned output canaries, failure output preservation, registration resets, first-frame retention, replacement release, black/blank frames, port separation and close/reopen generations. Main and overlay presentation are exercised. Four label cases, eight related VideoOut cases and 14 CPU regressions passed without skips at their earlier tested integration; no standalone title startup or FPS improvement is claimed.
• Removing the replacement-label release makes the regression fail; restoring it makes the test pass. Production NID-patched API/helper probes also passed.
• The latest edits relocate the byte-identical label test function/dispatch, register label modes separately and place the debt entry beside related buffer behavior. Merge-tree checks merge the branch cleanly with feat(videoout): present reserved flips from tagged GPU completion #5539, fix(libSceVideoOut): return RESOURCE_BUSY when a bus is opened twice #4863, feat(libSceVideoOut): implement sceVideoOutSetFlipMaster and sceVideoOutClearFlipMaster #5239 and feat(agc): replay proven finite stencil reference exports #5466. These are independent features and require no dependency.
• This branch also merges cleanly with newer main feddf7f4c654; the full CI above remains tied to its recorded earlier source/base. Conventions and whitespace checks pass.

Checklist

• Based on main; merges cleanly with current main, with validation revisions recorded above
• One topic per PR; follow-ups go in a new PR
• No comments in code except technical debt
• No silent stubs added
• No notes, investigation files or images added to the repository
• No new third-party code
• Generic behaviour, not specific to one title
• Depends on: none
• Unblocks: PPSA21564 Astro Bot (PPSA21564) #357 (buffer-label import and host presentation behavior)
• GPUs tested: AMD Radeon RX 6650 XT / RADV Mesa 26.2.4 and software lavapipe / Mesa 26.2.4, Arch Linux; native validation scope above
• AI-assisted: yes

[github-actions]

Progress report (ce5c839 → d1de55f)

📈 System libraries: 88.19% (+0.01%, +1 implemented functions)

✅ 1 implemented

Library	Name
libSceVideoOut	sceVideoOutGetBufferLabelAddress

[adriadam10]

Checked the label array against shadPS4 and fpPS4 (null output, invalid handle, count 16), the registration reset and the release of the previous buffer on replacement/black/blank flips. Built and ran video_out_flip_labels and video_out_flip_labels_main on a real X display (both pass; they skip under the offscreen CI driver). Removing the release in processFlip makes the test fail, restoring it passes. Merging once the full Build is green.