Amd RX560D slow after upgrade.

OK, I got two new rx560D in november, and I need to use Slackware current, because Slackware 14.2 it didn't worked.
That time the Slackware current came with kernel 4.9.50, mesa 17, xorg-server 1.19.3 and xf86-video-amdgpu-1.3.0. It worked perfect, the blender viewport was really fast, it holds about 30 trillions of faces, it was really impressive.
Ok I have two machines (I bought two rx560d) in one machine I keep upgrading slackware current, and after the ship of the new kernel (I think 4.10...) things became very slowly, the viewport was very slowly, it reach something like 6 trilions and it became horrible slowly. Its hard to track what was wrong because when you upgrade slackware current it upgrade all other packages, not only the kernel.
So after a year using waiting for some news, I tried the lastest kernel 4.19 in the lastest slackware 16/09/2018 (xorg-server-1.20.1-x86_64-1, mesa-18.2.0-x86_64-1, xf86-video-amdgpu-18.1.0-x86_64-1) and even with the lastest kernel, compiled with all those news libraries the viewport is still slow (I tried to upgrade blender too, didnt work).
So I tried to go back to the kernel 4.9.50 that was still working with the other pc (is the exactly the same pc, I just have two because of my job) and this old kernel didnt work, the X didnt initiate, and I got a black screen, and system froze, and I have to restart using the button.). I think that the kernel is too old for the libraries.
So I got the other pc with the all old slackware curret (that one with the kernel 4.9.50 its from 15/09/2017) and upgrade the kernel, to the lastest one, I compiled it by hand, and know what!? The viewport got slowly, about 6 trillions of faces it became unusable. Even with the old libraries (xorg, mesa and amdgpu), So I think that something wrong with amdgpu driver in the kernel, or they are doing it because they want to, I don't know.
Somebody please could help me?
Its already take one year with this problem and I don't know if I have to contact Amd, Linus or you guys. I already tried the lastest ubuntu, didnt work (because as I said the kernel was new) and I already tried the amdgpu property driver, but still slow (I think slower than the open one). But the driver that is in kernel 4.9.50, its awsome its about 5x faster. Please help me to fix this.
I'm from Brazil sorry my bad english.

Does Xorg.0.log report actual use of the amdgpu driver? If yes, have you thought to try the other FOSS X driver built into the server {modeset(0)}? If this doesn't help you, try reporting your issue to the amd driver developers on xorg-driver-ati@lists.x.org.

Yes, xorg.0.log report amdgpu is in use.
I dont know what is FOSS X diver or modeset 0, but I made a xorg.conf specifying the amdgpu and even other things, and didnt work, I will report to the developers as you said.

Thank you.

Originally Posted by drigohighlander I dont know what is FOSS X diver or modeset 0.

Modeset(0) is the Xorg.0.log name for the other free (FOSS) driver suited for use with AMD CPUs. If you uninstall xf86-video-amdgpu or xserver-xorg-video-amdgpu or whatever Slackware calls the amdgpu driver, X should automatically use modeset(0). Maybe it will be more satisfactory than what you have now.

Hi, I tried modeset(0) didn't work.
And I tried to post the bug in xorg-driver-ati@lists.x.org, they completly ignored me, and I posted twice.

Nobody can help me?

Originally Posted by drigohighlander Hi, I tried modeset(0) didn't work.

How exactly did you try? Can you pastebin or otherwise share your Xorg.0.log for us to see?

And I tried to post the bug in xorg-driver-ati@lists.x.org, they completly ignored me, and I posted twice.

So I see. You can also try xorg@lists.x.org. Make sure to not use HTML email. That may be why your messages were ignored.

and upgrade the kernel, to the lastest one, I compiled it by hand...

Did you enable AMDGPU at least as a module in the kernel config when you compiled it? I'll paste the AMDGPU settings of my kernel config so you can compare:

cli% grep AMDGPU /boot/config-generic-4.15.15 
CONFIG_DRM_AMDGPU=m
# CONFIG_DRM_AMDGPU_SI is not set
# CONFIG_DRM_AMDGPU_CIK is not set
CONFIG_DRM_AMDGPU_USERPTR=y
# CONFIG_DRM_AMDGPU_GART_DEBUGFS is not set