Display

Part of Hardware plan.

Panels

2× 1440×1600 VS035ZSM-NW0-69P0 MIPI DSI panels. These are the same panels used across the North Star revisions.
Optics from Project North Star. Revision not yet confirmed: Combine Reality Deck X or Northstar Next.

Drive path

North Star drives the panels through a DisplayPort-to-MIPI bridge. We drive them over direct DSI.
On the RB5, direct DSI means using both DSI ports, one per panel.
The existing panel driver from the RPi 5 build (RP1 support) will be ported, or replaced with an existing alternative: https://github.com/uwrealitylabs/rpi-panel-driver
Required: device-tree or panel-driver bring-up, plus DRM/KMS direct mode for Monado's compositor.

Software boundary

The compositor drives the panels. The Monado headset driver only describes them (resolution, refresh, distortion).

What selects the display

Layer	Code	Decides
1. Kernel	Device tree + panel driver + msm DRM	Which connectors exist (e.g. DSI-1, DSI-2) and their modes
2. Vulkan driver	Turnip (Mesa shared display code)	Exposes KMS connectors as Vulkan displays drivable without a desktop
3. Monado compositor target	Output targets in `src/xrt/compositor/main/`	Which display or window the compositor opens
4. HMD device	Display description in `xrt_device`	Resolution, viewports, refresh the compositor renders for

Monado targets: direct mode for PCs (X11 RandR, NVIDIA, Wayland DRM leasing), windowed (X11, Wayland), and VK_KHR_display picking a display by index. Selection follows platform defaults plus env vars/settings; recent Monado reorganized targets into factories, so read the current tree.

With no desktop, the VK_KHR_display target is the fit. Confirm early, since both can fail independently of our code:

Turnip on mainline exposes the RB5's DSI outputs as Vulkan displays.
Monado's Vulkan-display target works on that stack. Its display selection logic was designed for PC headsets attached to desktops.

The dev kit's HDMI output is also a KMS connector, so the target can be proven on a monitor first (Tracer bullet roadmap Stage 1).