The Linux kernel already supports the Realtek RTL8125D 2.5G Ethernet controller but additional handling is required to enable the revision B variant of this chipset, which will be coming in the next kernel cycle.

The Realtek RTL8125D is found currently in use by some Intel Arrow Lake motherboards for providing 2.5G Gigabit Ethernet. The Linux kernel support has support for the RTL8125D but special handling is needed for the newer "rev B" variant ahead of that revision appearing on upcoming motherboards and PCIe add-in cards.

[1]This merge to net-next tacking this hardware support onto the existing r8169 driver explains that besides the new device ID there is also different firmware needed:

"Add support for RTL8125D rev.b. Its XID is 0x689. It is basically based on the one with XID 0x688, but with different firmware file. To avoid a mess with the version numbering, adjust it first."

With that Realtek RTL8125D Rev B support now queued in net-next, it will be on its way to the Linux 6.14 kernel in the new year.



[1] https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/commit/?id=a14a429069bb1a18eb9fe63d68fcaa77dffe0e23