Sorry for necro, but I believe this may still be relevant.
Tested the image by @amazingfate with H68K running as my main router with heavy IO load (Gigabit fiber and home server running NAS and some virtual machines for various services which include multimedia streaming and torrents). While overall the system itself is stable, there are several major issues with networking:
* ETH0/ETH1 ports (Rockhip GMAC RTL8211F @ 1Gbps) cause insane ksoftirqd CPU load, especially when both ports are under load. This results in packet loss under heavy load. With one port used, the CPU usage is tolerable. But the system still can't max out a gigabit link, topping at 500-600mbps. I use one port for internet upstream.
* ETH2/ETH3 ports (PCI-E RTL8125 2.5G @ 1Gbps) work well... when they work. In my setup, one port provides upstream to a home server while the other provides upstream to all other devices via a 16-port managed switch (which has other switches daisy-chained - most of my network is wired). The switch-side port likes to disconnect by itself at random intervals for 4-5 seconds and then come back. The home server-side port does not do that but it too sometimes likes to just stop working with no errors (fixable by a soft-reset). Swapping ETH2/ETH3 connectors "swaps" the misbehavior. This makes me believe the misbehavior is directly caused by IO load, not specific interfaces.
Other minor issue is the front LEDs which aren't properly setup in the DTB file. Recompiling the DTS from kernel sources with all 3 LEDs added (GPIO assignments taken from Seeed's OpenWRT fork DTB) fixes this. Not a big deal though.
Upgrading the r8125 module to the latest version does not help. There's a 6.1 kernel available which should work with the RK3568 SoC (sans the multimedia stuff which I don't care about) but I do not have a working DTB file to test it.
Next thing I'll do is take the device apart to check it's cooling setup to rule out any possible overheating issues with the RTL8125s.
