Synopsys DesignWare HDMI

Identity

Status — · not started

The driver is in the PINEPHONE_PRO kernel config (device dw_hdmi) and links into the build, but the PinePhone Pro does not expose an HDMI connector — any external display has to come up through USB-C DisplayPort alternate mode, which routes through the RK3399 TCPHY rather than the DW HDMI TX. Nothing in the current tree drives a DP-alt-mode handshake from the FUSB302 side, so even though the HDMI driver is compiled, it has never been exercised on hardware. On PineTab2 the DW-HDMI sibling block is the primary external output, but that’s a separate Phase 3 target.

Driver

• Our tree: src/sys/dev/drm/bridges/dw_hdmi/dw_hdmi_if.m — interface stub. The full driver source (dw_hdmi.c + rk_dw_hdmi.c) is layered in by the patch pipeline from the drm-subtree repo; entries are wired up in src/sys/dev/drm/extra_patches/files.bridges.
• Linux mainline: drivers/gpu/drm/bridge/synopsys/dw-hdmi.c (core)
• Linux mainline: drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c (RK glue)

Code lineage matches the Synopsys / Rockchip split used by dw_mipi_dsi. PineTab2 (covacat tree) actually exercises this driver and is the nearest reference for “does it work on FreeBSD.” On PinePhone Pro, the practical first step is the FUSB302 / TCPHY DP-alt path: the cross-driver audit documents the missing source-role plumbing in fusb302 and the SWITCH2 entanglement in rk818 that gates an OTG/DP transition.

Open work

• Connect a USB-C DP-alt hub and run a tracer on TCPHY to confirm the alt-mode handshake — none of this has been attempted yet.
• DW-HDMI audio infoframe support — Linux exposes this through dw-hdmi-audio; FreeBSD has no equivalent.
• Coordinate with the FUSB302 source-role roadmap before treating this as bring-up work.

Related

• Hardware reference — HDMI row of the display table.
• Component: FUSB302 — gates DP-alt-mode entry.
• Cross-driver audit — fusb302 + rk818 source-role section.