Re: [gentoo-user] AMDGPU KMS Problems

[Rich Freeman]

On Wed, Jul 12, 2017 at 5:34 PM, jdm <jdm@××××××××××××.uk> wrote:
>
> I checked the config of the kernel (inc firmware) and could not find
> an issue. I then tried arch/fedora/ubuntu and all froze at boot and then
> worked with nomodeset.

Ok, this is pointing to a likely hardware issue IMO - I gotta imagine
that one of those distros would have noticed the RX 480 not working -
it is hardly an obscure card.

>
> 1) Is this likely to be a kernel issue (amdgpu drm)?

Probably not, imo.  However, I would try booting using a mainline
kernel (4.12 right now) just to confirm.  Any distro would be fine -
but try it on the bleeding edge kernel on one of them.

> 2) Could this be a firmware issue (amd)?

Maybe, but probably not.  You might want to check if your motherboard
has any published issues.  I'd think that amd would be pushing their
motherboard partners to support their cards.

> 3) Could this be a motherboard/processor issue?
> 4) Can you think of any ways round this so I can use the RX 480 gpu

I suspect it is some kind of motherboard-GPU issue.  Maybe it is
firmware - I'd search for that.  Some kind of power issue could also
be the problem.  Maybe your board has issues supplying enough power (I
understand the RX 480 draws quite a bit through the PCI slot), or
maybe the new motherboard+CPU+RX480 combo is stressing your power
supply (either overall, or on one of the rails).  Granted, if your old
card was also a radeon it probably was also a power hog.

Those are just the things I'd probably poke at - somebody else might
have other ideas.  Hopefully you'll get it working - I doubt I'll need
an RX 480 but I probably will move to Ryzen sometime soon now that it
is starting to mature on linux (though I wouldn't mind seeing it
supported in a longterm kernel first, especially since I'm using btrfs
and zfs on this box).

-- 
Rich