Mainline boot splash: laptop proofs for group 1

Host evidence only (laptop claim). No board, serial port or lock was touched, nothing was flashed, and no physical, QEMU or boot result is claimed. Base revision 5675e5db, branch impl/mainline-splash-2026-10-12, 2026-10-12. Retained out-links: ~/.local/state/tdisplay-k230/retained-builds/mainline-splash-2026-10-12.

1.1 Reserved-memory node on the mainline tree

The node is in nix/dts/k230-tdisplay-mainline-drm-common.dtsi, included by the panel, HDMI, HPD-monitor and hotplug DTS files. nix/device-tree-mainline-drm.nix now takes bootSplashConfig ? import ./boot-splash.nix and passes the three -DK230_SPLASH_FRAMEBUFFER_* flags, the same constant the vendor tree (nix/device-tree.nix:96-98) and U-Boot’s Kconfig fragment use. The base k230-tdisplay-mainline.dts and nix/device-tree-mainline.nix are unchanged.

for a in mainlineDrmHotplugDeviceTreeNormalName mainlineDrmDeviceTreeNormalName \
         deviceTreeMainlineDrm deviceTreeMainlineDrmHdmi \
         deviceTreeMainlineDrmHpdMonitor deviceTreeMainlineDrmHotplug; do
  flock /tmp/k230-nix-build.lock nix build .#$a --max-jobs 1 --cores 4 --out-link $R/$a
done   # all exit 0
fdtget -l <dtb> /reserved-memory               # framebuffer@10000000
fdtget -t x <dtb> /reserved-memory/framebuffer@10000000 reg   # 0 10000000 0 400000
fdtget -p <dtb> /reserved-memory/framebuffer@10000000         # reg no-map phandle

Daily DTB: /nix/store/s95i342w62j6zdnpkz27zzqjsgydxww2-k230-mainline-drm-hotplug-dtb-normal-name/k230-tdisplay.dtb (.#mainlineDrmHotplugDeviceTreeNormalName). /memory@0 reads 0 0 0 40000000. All four mainline DRM DTBs print reg = 0 10000000 0 400000.

Reserved range 0x10000000..0x10400000 against the U-Boot load map (firmware/stage1/tdisplay.env:27), using the splash bundle’s real sizes:

The logo itself is loaded into this range by U-Boot, not by these entries. The kernel image_size is the Image header value; run-time BSS beyond it was not measured but would need to exceed 0xd4 MiB to reach the range.

1.2 Handoff in source and the kernel build

See the “Mainline kernel: stage-1 splash handoff” section of docs/evidence/kernel-patches.md (files, lines, log strings, drop conditions, and the fbdev-client finding). No driver was patched. Kernel: /nix/store/f3rnipvbc5vqam8kwdmn3wgcl5rbz9yx-linux-riscv64-unknown-linux-gnu-7.3.0-rc5.

1.3 Splash image on the mainline shell

New attributes: nixosConfigurations.k230-mainline-drm-shell-splash (extendModules, k230.panelConsole = lib.mkForce false), .#sdImage-mainline-splash, and .#kernelMainlineDrmShellSplashBootFiles (nix/coherent-shell-boot-files.nix gained an optional splashImage that adds logo.xrgb, checked at 2799104 bytes, to the bundle and its SHA256SUMS; existing bundles are unchanged). The default at flake.nix:130-134 stays true; kernelParams evaluate to console=tty0 first for k230-mainline-drm-shell and without it for the splash variant.

flock /tmp/k230-nix-build.lock nix build .#sdImage-mainline-splash --max-jobs 1 --cores 4 --out-link $R/sdImage-mainline-splash
# -> /nix/store/ad30vws162xhr00x747xxilpjbga7qk1-k230-sd-image.img
flock /tmp/k230-nix-build.lock nix build .#kernelMainlineDrmShellSplashBootFiles --max-jobs 1 --cores 4 --out-link $R/kernelMainlineDrmShellSplashBootFiles
# -> /nix/store/kjlnrxv8vdk92lh84w2bkd1v0mx456hy-k230-coherent-shell-boot-files
python3 docs/evidence/mainline-boot-splash/inspect-image.py $R/sdImage-mainline-splash <fdtget> > docs/evidence/mainline-boot-splash/inspect.json

inspect.json reports PASS: logo.xrgb present at 2799104 bytes, bootargs.txt without console=tty0, and the image’s k230-tdisplay.dtb carrying the reservation. The bundle’s logo.xrgb is 2799104 bytes; its system and Image are the same derivations as the image’s.

Limits

Nothing here shows that the panel stays lit, that /dev/fb0 is absent, or that the first modeset is free of a dark frame; those are hardware tasks 2.1 to 2.4. No binary is committed. The U-Boot logo-device finding is in the commit report, not in this file.