Mesa To See Better Infrastructure For Supporting Render-Only GPUs

With many current ARM/embedded devices having their GPU render and display hardware split into different blocks, Mesa is seeing infrastructure improvements for making it easier to support new platforms in this split configuration.

Based off code from the VC4 "Raspberry Pi" driver and then adapted to the Vivante "Etnaviv" Gallium3D driver and i.MX, the new KMSRO code will developers an easier path for bringing up support for these render-only GPUs/drivers. The "kernel mode-setting render-only" code is intended to more easily bring up these platforms where a driver is responsible for rendering only and then passing the contents off to a different KMS driver for display. The KMSRO code is based on VC4's pl111 driver code that does PRIME sharing with different KMS-only display devices.

This does allow better code sharing with already nearly 300 lines of code removed as a result of the i.MX winsys being able to be deleted with it leveraging now the new KMSRO code. This infrastructure will also benefit future driver work such as for the maturing Panfrost driver with its ARM Mali hardware support in a similar configuration.

More details via this patch series.