https://bugs.freedesktop.org/show_bug.cgi?id=106306
--- Comment #5 from Alex Deucher alexdeucher@gmail.com --- You need to make sure the PP_OVERDRIVE_MASK flag (bit 14) is set. E.g., amdgpu.ppfeaturemask=0xfffd7fff See the documentation in the driver for more: https://cgit.freedesktop.org/~agd5f/linux/tree/drivers/gpu/drm/amd/amdgpu/am... Also, If the vbios on the particular board does not support overclocking, the functionality is not exposed on 4.17 IIRC.