====== The displays & cluster override ======

The dash has **4 physical panels**, but the i.MX6 drives only **2 video outputs**:

^ Logical display ^ Output ^ Physical panel ^
| ''[0]'' Integrated screen | LVDS (built-in) | **center infotainment** (the Android UI) |
| ''[1]'' HDMI screen | HDMI (presentation) | **right small portrait panel** (cluster media area) |

The **driver speed/SoC cluster** and the **left portrait panel** are **separate ECUs — not
reachable** from this Android. The reachable right panel is only the **top-left crop** of the HDMI
canvas (~264 × 464 px, portrait, with a slight keystone skew to allow for).

===== Painting above the OEM =====

The OEM paints the cluster from a very high window layer. A normal application window is drawn
//under// it. **Because a system-signed app runs as uid.system, it can add a system-level overlay
window bound to display [1]** that lands **above** the OEM layer, so our content wins.

**Two gotchas that cost hours:**
  - ''screencap'' does **not** capture this overlay (hardware-overlay path) — **verify on the
    physical panel**, not a screenshot.
  - The overlay must be **fully opaque** when active; a partly-transparent fill lets the OEM show
    through.

**Implemented:** a speed-limit sign + "SLOW DOWN" appears on the right panel when the over-speed
rule fires, and is transparent otherwise. See [[speedwarning]].