loading drm crashes system

[Greg V]

On Thu, Jan 28, 2021 at 18:27, Scott Bennett via freebsd-x11 
<freebsd-x11 at freebsd.org> wrote:
> 	d) which Radeon cards are no longer supported and which are still
> 	   supported?
> 
>      That last one is important to those of us despairing of ever 
> having working,
> safe-to-use graphics support again in FreeBSD on their systems.  If 
> what was
> working before has been broken without warning (or, apparently, 
> concern on the
> part of the graphics team) and is likely never to work again in the 
> future, then
> what should we look to obtain as replacement hardware that is 1) not 
> too new to
> work, 2) not too old to work, 3) not too costly for our budgets, and 
> 4) likely
> to continue to work long enough to justify the cost before it, too, 
> gets broken
> permanently and without warning?  We users need some information, 
> some guidelines.

It is pretty well known that amdgpu is in a much better shape than 
legacy radeon.

So the answer is kinda obvious and has been floating around on mailing 
lists and chat rooms for a long time:
AMD GCN architecture cards are actually well supported,
while pre-GCN relics (TeraScale/R600 and older) are "best effort" 
hopefully-supported-but-have-a-debugger-ready.

Polaris (RX 460/470/480/550/560/570/580/590) and Vega (56/64/FE/VII) 
are the two recent generations that got particularly popular, many many 
people actually use them heavily, they are 100% the best choice 
currently.
But I would expect earlier GCN chips (Tahiti, Bonaire, Tonga, Pitcairn, 
Hawaii, Fiji, etc.) to work about as well generally, I don't remember a 
single model-specific complaint from users of these generations.

As for what's too new:

- currently "Big Navi" (RX 6800/XT/6900) is really 100% too new, we'll 
have to jump from 5.4-5.5 to >5.10. I would like to get one of those 
eventually, when the market becomes less ridiculous.
- Renoir APUs (Ryzen 4xxx integrated graphics) are too new for the 
current stable drm 5.4, they do work on my 5.5-wip-amd-pr branch though 
https://github.com/freebsd/drm-kmod/pull/45#issuecomment-757333394 \o/
- Navi 1 (RX 5500/5600/5700) I think just works on the default current 
versions of everything?? Or maybe sort of requires 
https://github.com/freebsd/drm-kmod/pull/45 ? Several people use it 
already just fine.