Comment # 7 on bug 102300 from Michel Dänzer

According to the log file, the ASUS monitor only lists the 60 Hz 1920x1080 mode
in its EDID. So it seems clear that's what the monitor wants to be fed, but for
some reason we don't seem to be generating it properly.

Any chance you can try if a kernel built from the amd-staging-4.12 or
amd-staging-drm-next branch of https://cgit.freedesktop.org/~agd5f/linux/ with
CONFIG_DRM_AMD_DC=y works better?