Describe the bug: When using amdgpu, white-on-black horizontal lines intermittently flash on right half of screen. See video attached below in Screenshots FreeBSD version: FreeBSD fbsd 14.0-CURRENT FreeBSD 14.0-CURRENT #0 main-n258691-24cf7a8d628: Thu Oct 20 07:55:17 UTC 2022 root@releng1.nyi.freebsd.org:/usr/obj/usr/src/amd64.amd64/sys/GENERIC amd64 pciconf: vgapci0@pci0:9:0:0: class=0x030000 rev=0xc8 hdr=0x00 vendor=0x1002 device=0x1638 subvendor=0x1043 subdevice=0x8809 vendor = 'Advanced Micro Devices, Inc. [AMD/ATI]' device = 'Cezanne' class = display subclass = VGA DRM KMOD version: drm-510-kmod 5.10.113_7 drm-kmod 20220907_1 To Reproduce: Install either 13.1-RELEASE, 13.1-STABLE, or 14.0, install drm-kmod package, enable amdgpu by adding kld_list="amdgpu" to /etc/rc.conf, and log into a console. Screenshot: https://user-images.githubusercontent.com/11449161/198061203-8056e97d-7a3d-4ccb-945f-fcc6423e88cb.mp4 Additional context: It appears support for vendor=0x1002 device=0x1638 graphics card has been added: https://github.com/freebsd/drm-kmod/blob/5.10-lts/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c#L1102 Same issue presents on any FreeBSD version listed above, whether built from source or installed from snapshot. Disabling video mode using hw.vga.textmode=1 does not resolve the issue. The issue carries over into an X session. Notably, the issue disappears when compiling anything, whether in the console or X. Github issue previously opened under freebsd/drm-kmod at https://github.com/freebsd/drm-kmod/issues/213