DragonFlyBSD Updates Its Radeon/TTM Driver Code Against Linux 3.18 Bits
Like other BSDs, DragonFlyBSD continues re-basing their Radeon and Intel driver code against what's in the mainline Linux kernel given that's where the vendors are working on the open-source graphics support without any catered driver to the BSDs, with the exception being NVIDIA and their binary driver being offered with official FreeBSD support. But due to the changes needed when re-basing the code in adapting to the latest interface changes, it's quite a burden to maintain. While the Linux 5.1 kernel is expected to be out this weekend, DragonFlyBSD is generally playing with late 3.x Linux kernels and early 4.x bits.
Back in 2017 there was an update of the Radeon code against Linux 4.7 but that was later reverted in September 2017 over causing issues with some Radeon setups at the time.
With the NVIDIA binary driver exception, generally for the BSDs, the older GPUs are a better bet.
After not seeing much work last year or this year so far for the Radeon porting to DragonFlyBSD, as of Friday the Radeon and TTM memory management code was updated to Linux 3.18. Yes, the kernel that was released at the end of 2014.
For what it's worth though, most of the Intel/Radeon Linux DRM porting to DragonFlyBSD is being done solely by François Tigeot. So he does deserve applause for his work in this space, but for those expecting up-to-date AMD Radeon GPU support on DragonFlyBSD, don't hold your breath.