ATI没有freebsd的驱动。
需要在内核配置文件中加入下面两行
device drm # DRM core module required by DRM drivers
device i915drm # Intel i830 through i915
device mach64drm # ATI Rage Pro, Rage Mobility P/M, Rage XL
device mgadrm # AGP Matrox G200, G400, G450, G550
device r128drm # ATI Rage 128
device radeondrm # ATI Radeon
device savagedrm # S3 Savage3D, Savage4
device sisdrm # SiS 300/305, 540, 630
device tdfxdrm # 3dfx Voodoo 3/4/5 and Banshee
然后重新编译内核。