Round 25: video never probed — console env wiring; ENV_IS_NOWHERE + krane.env stdout mux

RESEARCH.md

@@ -960,3 +960,45 @@ New checkpoints (mt8183_scanout.c + video-uclass.c video_post_bind):
 | magenta + red@840 | no plausible scanout address |
 | magenta + gray | geometry OK; failure later (clear/probe tail) |
 | cyan/white appear | video_clear + post_probe reached — back on the R19/20 tree |
+
+## Round 25 — [REVERSED] not a probe failure: the video device was never probed (console env wiring)
+
+Round 24 (`03fc7b4d…`): **purple, no magenta, no red error bands** —
+the driver matched the DT node and bound, but device_probe was never
+called, and none of the probe's error paths ran. Root cause is in
+common code, not the driver:
+
+- stdio_add_devices()'s probe-all loop over UCLASS_VIDEO is compiled
+  OUT when CONFIG_SYS_CONSOLE_IS_IN_ENV=y — and that defaults to y via
+  CONSOLE_MUX (inherited from the pumpkin defconfig fork).
+- With SYS_CONSOLE_IS_IN_ENV, console_init_r() reads env stdout/stderr
+  and muxes via iomux_doenv(). There was NO environment (and the env
+  backend was MMC — inherited, wrong for a depthcharge payload), so
+  the names were NULL, console_search_dev() never saw the string
+  "vidconsole", the lazy stdio_probe_device(name, UCLASS_VIDEO) never
+  fired, and the console fell back to serial only. The video device
+  was never probed → no clear, no cyan/white, no banner. Screen keeps
+  the init bands.
+
+### Fix (payload `e4bdd875…`, flashed, cmp+vbutil OK)
+
+- CONFIG_ENV_IS_NOWHERE=y (drops the MMC env dependency inherited
+  from pumpkin — correct for a payload stage, deterministic default
+  env);
+- new CONFIG_ENV_SOURCE_FILE="krane" +
+  board/mediatek/mt8183/krane.env:
+    stdin=serial
+    stdout=serial,vidconsole
+    stderr=serial,vidconsole
+  so console_init_r() → iomux_doenv() → console_search_dev
+  ("vidconsole") → stdio_probe_device → probes the video device
+  (driver probe → clear → vidconsole registered) → banner muxed to
+  serial + screen.
+- R24 instrumentation kept for this round.
+
+### Expected
+
+blue → blinks → hold → green/orange/blue/red/yellow bands → magenta
+(probe entered) → screen CLEARS black → gray (geometry) → cyan/white
+(video clear/probe) → **white-on-black banner** (or a red failure
+band: y=800 lbio, y=820 fmt, y=840 scanout).