5K @60Hz resolution

[sunarowicz]

Can anybody share personal experience in getting Raxda Rock 5B or any other similar RK3588 device to run with 5K resolution at 60Hz over HDMI? SBC is said to support up to 8K@60 on HDMI1. The monitor I use supports 5K@30,60,120 on HDMI. I use certified Ultra High Speed HDMI cable included by DELL with the monitor. But in Ubuntu 5K is available only at 30Hz.

I use Joshua's 24.04 Ubuntu with the 6.1.0-1025-rockchip kernel.

I already tried to add rock-5b-hdmi1-8k.dtbo overlay and to add and use new "5120x2160_60.00" mode with xandr. But nothing worked to me.

I appreciate any, preferably positive:-) info on this topic.

[sunarowicz]

I tested the monitor with laptop. While connected over Thunderbolt, monitor runs at 5K@60Hz with no issues. But when connected over HDMI 2.0 laptop port, it (obviously) runs at 5K@30Hz only. This leads me to question whether (although advertised so), the Rock's 5B HDMI port is really HDMI 2.1 or 2.0 only? To be honest, I don't see any other possible explanation of this issue than this right now.