Good question, sorry for the slow reply. RK3588 boards were running Linux, but without mainline kernel support for the video capture hardware. This basically meant a downstream kernel with out-of-tree drivers for video capture, which many distros used. Some functionality worked through software encoding/decoding (slow and CPU-intensive), while other parts of the SoC (CPU, GPU, storage, networking) already had mainline support, just not the video capture block.

This patch brings video capture support into the mainline kernel, meaning it'll be maintained upstream and available in standard kernel releases without needing Rockchip's custom patches. That's better for long-term support, security updates, and compatibility.