OS: FreeBSD 12.2-STABLE
HW: ATI Radeon HD 2400 PRO (RV610 GPU)
After 12.2 upgrade, using the radeonkms module as shipped with the kernel, everything worked but I always got that
libGL error: failed to load driver: radeon
error for all applications using OpenGL, and in general, graphics appeared to be slow (e.g. when switching virtual screens, xterm took a noticable time to redraw a terminal window).
Research indicated to use drm-fbsd12.0-kmod instead of the modules shipped with kernel.
Initial attempts to use these resulted in the system quickly panicking after a few minutes of X11 operation. Rebuilt all modules (and GPU firmware) today, now it appears to be stable, and the dreadful "failed to load driver" message is gone. Overall graphics performance appears OK now. Most OpenGL applications to work well. However, cad/horizon-eda (which requires OpenGL 3.2 as minimum) triggers kernel errors, and yields garbage in its drawing areas.
forbidden register 0x00028b90 at 1215
Invalid command stream !
Using the deprecated system-supplied kms modules, horizon-eda worked without problems.
Created attachment 223459 [details]
I was too fast.
Using the 3D viewer from cad/kicad-devel, the system panicked again.
Coredump info attached.
I'm reverting to the legacy module by now, for stability.