Round 30: fb text logger + abort dump (ESR/ELR/FAR) on panel

RESEARCH.md

@@ -1133,3 +1133,31 @@ Sub-checkpoints inside the probe (all 20-row bands below magenta):
 Reboot and report which of mint/violet/pale-yellow/pale-cyan appear
 below the magenta band. The first missing one identifies the aborting
 statement.
+
+## Round 30 — real text logging: fb font logger + abort dump on panel
+
+Round 29 result: probe entered (magenta), then frozen — but the user's
+color report ("light green") is ambiguous between mint (y=520) and
+pale yellow (y=560), and band combinatorics are getting unreadable.
+User proposed real logs — agreed; implemented:
+
+- mt8183_scanout.c now has krane_fb_log() / krane_fb_log_hex(): a
+  minimal framebuffer text logger using the built-in 8x16 font
+  (video_font.h), drawing white text into the live scanout (bottom
+  rows, y>=1700), with a static cursor and per-call dcache flush.
+- Probe steps now emit text: PROBE → REVIVE → MAPTBL → LBIO → FMT →
+  GEO (bands kept for redundancy).
+- krane_fb_log_abort(esr, elr): reads FAR (CurrentEL-aware mrs) and
+  draws "ABORT! ESR=0x… ELR=0x… FAR=0x…" on the panel; wired into
+  arch/arm/lib/interrupts_64.c do_sync() (TEMPORARY). With
+  CONFIG_PANIC_HANG=y the screen freezes with the dump visible —
+  even though the pre-console printf buffer stays invisible.
+
+### Round 30 payload (`60f5dba8…`, flashed, cmp+vbutil OK)
+
+### Ask
+
+Reboot and report: (a) the text line(s) at the bottom (PROBE REVIVE
+MAPTBL LBIO FMT GEO — where does the sequence stop?), and (b) if an
+"ABORT! ESR=0x… ELR=0x… FAR=0x…" appears, transcribe the three hex
+values.