Radeon drivers are specific per Radeon microarchitecture and Radeon
microarchitecture version. 

The Radeon microarchitectures to date are TS 1, TS 2, TS 3, GCN 1, GCN
2, GCN 3, GCN 4, GCN 5 (TS = TeraScale and GCN = Graphics Core Next),
in that ascending chronological order. [1]

First, thank you very much jsg@ for that you committed full OpenBSD
kernel support for the radeondrm(4) driver today! [2]

Previously, while Xorg's radeondrm(4) driver supported all cards up to
GCN 2, OpenBSD's kernel supported the Radeons up to GCN 1 only. The
radeon(4) man page listed all cards up to GCN 2, but only the cards up
to GCN 1 were actually supported by OpenBSD.

jsg@'s diff today extends radeondrm(4) to support Radeons up to GCN 2.

The major move with Radeon graphics cards today, is their move from the
radeondrm(4) driver (called "xf86-video-ati" by Xorg and "radeon" on
Linux) [3], to the "amdgpu" driver (called "xf86-video-amdgpu" by Xorg)

All new Radeon are driven by the amdgpu driver:

The radeondrm driver supports all Radeon cards up to and including GCN
2. GCN 2 was released 2013 and the last GCN 2 card was released 2015.
No more GCN 2 cards will be coming.

The amdgpu driver supports all new Radeon cards from GCN 1.2 and up.

This means the amdgpu driver is needed for GCN 3 and newer Radeons, and
GCN 3 cards started coming to the market 2014.

amdgpu(4) has not been ported to OpenBSD yet. [5]

I am not perfectly clear about the max feature set in the GCN 2 cards,
maybe I will make a post later about what you can and cannot do with
amdgpu(4) (not yet ported) vs. radeondrm(4) cards, however more modern
features like Displayport 1.4 and 1.3 support, support for higher
resolutions, MST (Multi-Stream Transport), newer video codecs with
higher resolutions etc., appear to be only in the newer GCN 5 and GCN 4
cards, which are supported only by the amdgpu driver.

The Radeon GPU:s are important in OpenBSD's ecosystem as they are the
only way to increase graphics functionality, that not involves changing
CPU to Intel's latest, and hence change motherboard and other hardware.

Do you have plans to port amdgpu?

Would particular hardware donations or other donations be of help?


[1] https://en.wikipedia.org/wiki/List_of_AMD_graphics_processing_units



[2] https://marc.info/?t=151664661500004&r=1&w=2

[3] http://man.openbsd.org/OpenBSD-6.3/radeon.4




[4] https://www.phoronix.com/scan.php?page=news_item&px=AMDGPU-DC-Accepted






[5] Those I talked to clarified this however also relevant refs:

As seen by the absence of any "amdgpu" man page:


No "xf86-video-amdgpu" directory among the Xenocara drivers:


As of today on misc@ "amdgpu" has only been mentioned once, which was in the 
context of not being supported:


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