Direct firmware load for $something_mc.bin failed with error -2

-2 means that the file was not found. Install linux-firmware or whatever the name for the linux firmware package is of your distro. Install it and reboot. Then that error should be gone. If it’s not, double check if $something_mc.bin exists and check where to get it. It might just not be packaged by the maintainers of the package.

for indexers:
Direct firmware load for amdgpu/polaris10_mc.bin failed with error -2