Hi,

I believe that while Pi is suitable for video playback up to 1080p only, it still would be nice to support larger screens for other not-so-demanding scenarios. At the moment, maximal screen size is hardcoded to 2048x2048 in vc4_kms.c.

Pi is capable of 4K (3840x2160@25Hz) output over HDMI (using fbturbo and custom hdmi_cvt or hdmi_timings line in config.txt), which is totally OK for displaying dashboards, demos, slideshows etc.