These are the packages that would be merged, in order:

Calculating dependencies ... done!
Dependency resolution took 1.58 s (backtrack: 0/20).

[ebuild     U  ] x11-libs/libdrm-2.4.134::gentoo [2.4.131::gentoo] USE="-doc -test -tools -udev -valgrind" VIDEO_CARDS="amdgpu* vmware (-exynos) (-freedreno) -intel -nouveau (-omap) -radeon (-tegra) (-vc4) (-vivante)" 427 KiB
[ebuild  N     ] sys-apps/amdgpu_top-0.10.4::gentoo  USE="-debug -man" 41009 KiB

Total: 2 packages (1 upgrade, 1 new), Size of downloads: 41436 KiB

The following USE changes are necessary to proceed:
 (see "package.use" in the portage(5) man page for more details)
# required by sys-apps/amdgpu_top-0.10.4::gentoo
# required by =sys-apps/amdgpu_top-0.10.4 (argument)
>=x11-libs/libdrm-2.4.134 video_cards_amdgpu