Xorg behavior was the same whether 15.1 (1024x768; poor; KDE3 and IceWM) or 15.2 (2560x1440; as expected; KDE3 and IceWM).
Discussion on https://forum.mxlinux.org/viewtopic.php?f=107&t=53413 suggested either needed kernel backporting is absent or broken, or newer X or some of its components are needed.
I enabled [noparse]X11:XOrg[/noparse] and added the following:
i+ | libdrm_amdgpu1 | package | 2.4.100-lp151.264.1 | x86_64 | X11XOrg
i+ | xf86-video-amdgpu | package | 19.1.0-lp151.64.2 | x86_64 | X11XOrg
i+ | xorg-x11-server | package | 1.20.7+0-lp151.601.1 | x86_64 | X11XOrg
i | xorg-x11-server-Xvfb | package | 1.20.7+0-lp151.601.1 | x86_64 | X11XOrg
but all that happened was more modules autoloaded on subsequent boots. Then I copied back the 15.2 kernel as in comment #12, rebooted, and X was working almost like in 15.2. Next I added Mesa from [noparse]X11:XOrg[/noparse], which pulled libLLVM9-9.0.1:
i+ | Mesa | package | 19.3.3-lp151.1067.1 | x86_64 | X11XOrg
i+ | Mesa-demo-x | package | 8.4.0-lp151.59.2 | x86_64 | X11XOrg
i+ | Mesa-dri | package | 19.3.3-lp151.1067.1 | x86_64 | X11XOrg
i+ | Mesa-gallium | package | 19.3.3-lp151.1067.1 | x86_64 | X11XOrg
i+ | Mesa-libEGL1 | package | 19.3.3-lp151.1067.1 | x86_64 | X11XOrg
i+ | Mesa-libGL1 | package | 19.3.3-lp151.1067.1 | x86_64 | X11XOrg
i+ | Mesa-libglapi0 | package | 18.3.2-lp151.23.9.1 | x86_64 | Update
Next Ctrl-Alt-BS, and it locked up. Rebooting got X back, but in VESA 2560x1440 rather than AMDGPU in 2560x1440, with vttys in 80x25 text mode.
Journal from lockup boot. 1.2MB
Journal from VESA 2560x1440/80x25 boot. 132KB
Looks like Mesa-libglapi0-18.3.2-lp151.23.9.1 probably caused the crash, but replacing it with 19.3.3, and upgrading to X11XOrg libdrm-tools-2.4.100, plus reboot didn’t get amdgpu back. Neither Mesa-libva-19.3.3.
Oops! Forgot to boot 15.2 kernel. Next boot, good vttys 1-6, but black screen on vtty7, and locked up again. :’(
Journal from latest lockup.
Found two more missed upgrading to X11XOrg:
libdrm2-2.4.100
libgbm1-19.3.3
Now X is running on amdgpu:
> inxi -GSxxza
System: Host: Easystreet Kernel: 5.3.18-lp152.3-default x86_64 bits: 64 compiler: gcc v: 7.5.0
parameters: root=LABEL=wd10p08s151 net.ifnames=0 mitigations=auto consoleblank=0 noresume
Desktop: KDE 3 wm: kwin dm: N/A Distro: openSUSE Leap 15.1
Graphics: Device-1: Advanced Micro Devices [AMD/ATI] Picasso vendor: ASUSTeK driver: amdgpu v: kernel bus ID: 08:00.0
chip ID: 1002:15d8
Display: server: X.Org 1.20.7 driver: amdgpu unloaded: fbdev,modesetting,vesa alternate: ati
resolution: 2560x1440~60Hz
OpenGL: renderer: AMD RAVEN (DRM 3.33.0 5.3.18-lp152.3-default LLVM 9.0.1) v: 4.5 Mesa 19.3.3 direct render: Yes
This is the inventory of packages from [noparse]X11:XOrg[/noparse]:
i | libLLVM9 | package | 9.0.1-lp151.41.1 | x86_64 | X11XOrg
i | xorg-x11-server-Xvfb | package | 1.20.7+0-lp151.601.1 | x86_64 | X11XOrg
i+ | Mesa | package | 19.3.3-lp151.1067.1 | x86_64 | X11XOrg
i+ | Mesa-demo-x | package | 8.4.0-lp151.59.2 | x86_64 | X11XOrg
i+ | Mesa-dri | package | 19.3.3-lp151.1067.1 | x86_64 | X11XOrg
i+ | Mesa-gallium | package | 19.3.3-lp151.1067.1 | x86_64 | X11XOrg
i+ | Mesa-libEGL1 | package | 19.3.3-lp151.1067.1 | x86_64 | X11XOrg
i+ | Mesa-libGL1 | package | 19.3.3-lp151.1067.1 | x86_64 | X11XOrg
i+ | Mesa-libd3d | package | 19.3.3-lp151.1067.1 | x86_64 | X11XOrg
i+ | Mesa-libglapi0 | package | 19.3.3-lp151.1067.1 | x86_64 | X11XOrg
i+ | Mesa-libva | package | 19.3.3-lp151.1067.1 | x86_64 | X11XOrg
i+ | libdrm-tools | package | 2.4.100-lp151.264.1 | x86_64 | X11XOrg
i+ | libdrm2 | package | 2.4.100-lp151.264.1 | x86_64 | X11XOrg
i+ | libdrm_amdgpu1 | package | 2.4.100-lp151.264.1 | x86_64 | X11XOrg
i+ | libgbm1 | package | 19.3.3-lp151.1067.1 | x86_64 | X11XOrg
i+ | llvm9-opt-viewer | package | 9.0.1-lp151.41.1 | noarch | X11XOrg
i+ | xf86-video-amdgpu | package | 19.1.0-lp151.64.2 | x86_64 | X11XOrg
i+ | xf86-video-fbdev | package | 0.5.0-lp151.29.6 | x86_64 | X11XOrg
i+ | xf86-video-vesa | package | 2.4.0-lp151.37.5 | x86_64 | X11XOrg
i+ | xorg-x11-server | package | 1.20.7+0-lp151.601.1 | x86_64 | X11XOrg
Sound still does not work.