Linux 6.5 Raspberry Pi "VC4" Graphics Driver Picking Up New HDMI Features

An initial batch of DRM-Misc-Next patches targeting the Linux 6.5 kernel later this summer were sent today to DRM-Next for queuing ahead of that next merge window.

Among this initial set of DRM-Misc-Next patches for Linux 6.5 are a number of HDMI controller improvements for the Broadcom VC4 DRM driver, which most notably is used by the Raspberry Pi single board computers.

These VC4 HDMI patches are various features that have been carried by the downstream Raspberry Pi kernel but not upstreamed to the mainline tree until the process now. Among the VC4 patches are for exposing a Broadcast RGB property for overriding the RGB range for the HDMI pixel range if the monitor's data is inaccurate. There is also support for exposing BT.601 and BT.2020 colorspace support. BT.2020 is notably the specification for Ultra HD TVs with standard dynamic range.

Aside from the VC4 driver work, today's DRM-Misc-Next pull also adds support for exposing the DRM connector ID to user-space via sysfs. These patches come from Google as at least under Chrome OS they are looking to better expose which port is deriving which displays even if going through a DisplayPort Multi-Stream Transport (DP MST) hub or other complex topologies.

More details on this initial batch of DRM-Misc-Next patches intended for Linux 6.5 via this pull request.