Hi,
The amdgpu driver from Linux 5.14 seems to require
IOMMU support, which was disabled by default in my
system's BIOS. My system (which has a Radeon RX 5700XT
GPU) successfully booted 5.14 after enabling it in
the BIOS. Previous 5.10 kernel also worked with IOMMU
disabled. I did not do any further investigations.
In any case the missing firmware files from the original
report are a red herring since the warnings either already
existed for 5.10 kernel (e.g. the one about navi10_mes.bin)
or are for quite recent GPUs, which were not yet supported
by 5.10.
Regards,
-- Sebastian