Raspberry Pi 4 / BCM2711 Display Pipeline Still Being Worked On For VC4 DRM Driver

Going back a number of months have been patches for bringing up the Broadcom BCM2711 display pipeline as found with the Raspberry Pi 4 SBC. That work still hasn't been mainlined but a fifth round of patches has now been sent out for review.

Eighty patches hit the kernel mailing list this morning for working on this BCM2711 display pipeline support for the VC4 DRM driver. The most notable beneficiary to this work is the Raspberry Pi 4. Due to this SoC now having two HDMI controllers and other fundamental changes compared to the prior Broadcom SoCs used by the Raspberry Pi and VC4 DRM driver, a lot of driver restructuring is needed to get this Direct Rendering Manager properly driving the displays. Some code has also been cleaned up in the process. For now, only HDMI support is enabled though testing is also happening with DPI and DSI outputs.

The v5 patches have been re-based against the latest kernel code, there are some fixes around 4K displays and dual outputs, and a number of other code fixes.

We'll see how this round of review goes and if possibly this display support could make it into the Linux 5.10 kernel later this year.