after upgrading to fedora 30 my radeon rx 460 stopped working and i can only use my integrated graphics .
i think i might have had some configuration in /etc/default/grub that was lost .
at first gnome info didn’t recognize it but now it shows :
processor : AMD® A10-7850k radeon r7, 12 compute cores 4c+8g × 4
graphics: AMD® Kaveri / AMD® Radeon ™ rx 460 graphics
problem there is no official guide for fedora so i implemented from archlinux : https://wiki.archlinux.org/index.php/AMDGPU
i did find this fedora guide : https://www.schotty.com/EL_And_Fedora/amdgpu_Plus_Fedora/
so i added
radeon.cik_support=0 amdgpu.cik_support=1
to grub kernel parameters but it still doesn’t work .
also note that i use hdmi cable .