Reader sent Geerling's CM4 PTP write-up, which shows two CM4s syncing to 10-15ns.
Our headline overclaimed ('impossible on a Pi 4') and our mechanism was wrong (we
blamed the bcmgenet MAC for not exposing a PHC).
The real story is better: the CM4 (BCM54210PE) and the 4B (BCM54213PE) report the
IDENTICAL PHY ID 0x600d84a2, so the kernel cannot tell them apart by asking the
chip. bcm-phy-ptp.c disambiguates by MDIO bus address instead — addr 0 = CM4,
proceed; addr 1 = 4B, return NULL. Ours is addr 1.
It is not a kernel config gap and not our RT patch: CONFIG_BCM_NET_PHYPTP=y and
CONFIG_NETWORK_PHY_TIMESTAMPING=y are both set. The driver loads, looks at the
board, and declines.
Correction is visible on the page rather than quietly patched. Credit to Geerling.
Starlight renders the logo as an <img>, so CSS can't reach inside it. The single
cream-on-near-black SVG left a cream wordmark on a cream page. Ship a light
variant with warm ink and the darker brass the light theme already uses.
The landing page's headline results table was rendering as a paragraph of raw
pipe characters. Astro applies remark-gfm to .md but it wasn't reaching the MDX
pipeline, so every .md page rendered tables fine and only index.mdx was broken —
which is exactly why it went unnoticed. mdx({remarkPlugins:[remarkGfm]}) fixes it.
cuckoo.warehack.ing stays as a permanent redirect; it was live briefly.
What the Raspberry Pi time-server guides get wrong on a Pi 4, with the
measurements. The headline artifact is a four-line pps-gpio patch: PREEMPT_RT
force-threads IRQ handlers, and pps-gpio takes its timestamp inside its handler,
so the realtime kernel puts a scheduler between the electrical edge and the
clock. IRQF_NO_THREAD takes RMS offset from 2468 ns to 199 ns.
- kernel/ the patch
- dashboard/ live status page (position hidden by default)
- docs-site/ the write-up (Astro/Starlight, brass, no tutorial section)
