So far, everything works out of the box on my ThinkPad T14 AMD with Manjaro 20.2 and Linux kernel 5.8 — except for the ethernet adapter.
The T14 comes with a
RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller and by default the
r8169 kernel module is used. However, after plugging in a wired connection, nothing happened. Not even a blinking led.
To resolve this issue, we need to get the kernel module for Realtek 8168 network cards:
pacman -S linux58-r8168
Also, we need to blacklist the r8169 module:
echo "blacklist r8169" > /etc/modprobe.d/r8169_blacklist.conf
After unloading the old module and loading the new one (rmod r8169 and modprobe r8168 or just rebooting) your wired connection should work flawlessly.