https://bugs.freedesktop.org/show_bug.cgi?id=109206
--- Comment #10 from cd chris@degree.at --- I also encounter this bug on my HP Envy x360 Ryzen 5 2500U.
What worked for me as a workaround was to first upgrade the kernel to 4.20.7, then remove "raven_dmcu.bin" and finally run "mkinitcpio -p linux".