Can you bisect?

Sure! 

I haven't git bisected a kernel before so I'll go and teach myself how to and report back as soon as I figure it out (I'm currently testing it with 4.20.16, which also seems to work). I apologize for the delay, I will keep you updated!

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c713a461459202504050305242cd854bad57837c seems the most likely candidate, it's the only significant change to gmc_v9_0_late_init between 4.20 and 5.0.

I guess the problem is actually in gmc_v9_0_allocate_vm_inv_eng though. Peter, what does

 scripts/faddr2line drivers/gpu/drm/amd/amdgpu/amdgpu.ko gmc_v9_0_late_init+0x114/0x500

say in the kernel build tree (in the state after building the binaries which generated the attached dmesg output)?

Yeah, that is a known problem.

Give me a moment to submit a fix to the mailing list.

I'm going to try to see if I can narrow things down a bit by finding the last commit that worked before the bug happened and then bisect the kernel there. I'm going to try to compile the kernels, install them, and then try rebooting and starting xfce4 one by one until I find the one that won't start.

I apologize in advance for the sluggishness, there are a lot of commits here and the computer boots very slowly, so this puts a bit of a bottleneck on how many kernels I can test in a given timeframe. I'll try to hurry as best I can and I'll try to keep this thread updated as I make progress on it. Right now I think I'll start at commit af0df68432f65915b2a316aa99eeeb588d4c65a2 since that one works, and I'll start working my way towards 5.0.0 from there to see if I can narrow down the right commit that borked the driver. 

> I guess the problem is actually in gmc_v9_0_allocate_vm_inv_eng though. Peter, what does...[truncated]

Sure. 5.0.2, which gave us that dmesg output, returned to this message when I tried to enter the commands as followed, this is what the screen looks like: 

> captain@morgans-revenge /usr/src/linux-5.0.2-gentoo/scripts $ ./faddr2line ../drivers/gpu/drm/amd/amdgpu/amdgpu.ko
> gmc_v9_0_late_init+0x114/0x500
> gmc_v9_0_late_init+0x114/0x500:
> gmc_v9_0_late_init at gmc_v9_0.c:?
> captain@morgans-revenge /usr/src/linux-5.0.2-gentoo/scripts $

I hope this might be what you are looking for? I wasn't sure what to enter so I looked for the drivers folder and then typed the rest in as it was.

Whoops, hit return too quickly. 

(In reply to Michel Dänzer from comment #3)
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/
> ?id=c713a461459202504050305242cd854bad57837c seems the most likely
> candidate, it's the only significant change to gmc_v9_0_late_init between
> 4.20 and 5.0.

Sure. I'll go and give this one a try first, actually. I'm out of time for the night but I can hop back on it first thing tomorrow.

Please try https://patchwork.freedesktop.org/patch/292720/ , it should fix the problem.

Great, I'll go try it on 5.0.2 and report back, thanks!

(In reply to Michel Dänzer from comment #7)
> Please try https://patchwork.freedesktop.org/patch/292720/ , it should fix
> the problem.

Splice the mainbrace! It worked like a charm! 

It worked, xfce4 started without a hitch this time with the new kernel. Thank you so much! 

What shall we do now? Is there a way to get that patch merged upstream?

It's on its way already, but it might take a while for it to land in a 5.0.y release.

Yay, glad to hear! 

I'm going to change it to fixed then, if that's okay with you guys? 

Thank you so much for the help.