X11 AMDGPU driver doesn't get loaded

[Bakul Shah]

On a Motile M142 with Ryzen 5 3500U, amdgpu.ko and amdgpu_*.ko firmware
gets loaded fine on boot -- installed from ports/graphic/drm-devel-kmod
as I am running -current. [the port compiled from the exact same kernel
sources as /boot/kernel/*]

But when I try to start X11, Xorg.0.log shows this:

(EE) modeset(0): [DRI2] No driver mapping found for PCI device 0x1002 / 0x15d8
(EE) modeset(0): Failed to initialize the DRI2 extension.

and it tried to load the framebuffer driver, which works fine. AIUI
it should be loading /usr/local/lib/xorg/modules/drivers/amdgpu_drv.so

The PCI vendor/device IDs are correct. I added a relevant entry for my
laptop in /usr/local/share/pciids/pci.ids but ktrace reveals the
pci.ids file is never accessed. I have been trying read Xorg code but
wondering if there is an easier way to debug this. Or if I can simply
specify loading the amdgpu_drv driver and bypass modesetting! 

BTW, is this a better place to discuss debugging this or irc or gitter
or the freebsd forums?

Thanks!
Bakul