Comment # 9 on bug 1215987 from Felix Miata

A different host, also with early GCN AMD GPU, with Slowroll created in same
fashion (clone of 15.5 upgraded), does not reproduce this:
# inxi -GSaz --vs --zl --hostname
inxi 3.3.31-00 (2023-11-02)
System:
  Host: fi965 Kernel: 6.4.12-1-default arch: x86_64 bits: 64 compiler: gcc
    v: 13.2.1 clocksource: tsc available: hpet,acpi_pm
    parameters: root=LABEL=<filter> ipv6.disable=1 net.ifnames=0
    radeon.si_support=0 amdgpu.si_support=1 noresume consoleblank=0
    mitigations=off
  Desktop: KDE Plasma v: 5.27.9 tk: Qt v: 5.15.10 wm: kwin_x11 vt: 7 dm: XDM
    Distro: openSUSE Tumbleweed-Slowroll 20231003
Graphics:
  Device-1: AMD Oland [Radeon HD 8570 / R5 430 OEM R7 240/340 Radeon 520 OEM]
    vendor: Dell driver: amdgpu v: kernel alternate: radeon arch: GCN-1
    code: Southern Islands process: TSMC 28nm built: 2011-20 pcie: gen: 1
    speed: 2.5 GT/s lanes: 8 link-max: gen: 3 speed: 8 GT/s ports:
    active: DP-1,DVI-I-1 empty: none bus-ID: 01:00.0 chip-ID: 1002:6611
    class-ID: 0300 temp: 48.0 C
  Display: x11 server: X.Org v: 21.1.9 compositor: kwin_x11 driver: X:
    loaded: amdgpu unloaded: modesetting alternate: fbdev,vesa dri: radeonsi
    gpu: amdgpu display-ID: :0 screens: 1
  Screen-1: 0 s-res: 2560x2490 s-dpi: 120 s-size: 540x525mm (21.26x20.67")
    s-diag: 753mm (29.65")
  Monitor-1: DVI-I-1 mapped: DVI-I-0 pos: top model: Dell P2213
    serial: <filter> built: 2012 res: 1680x1050 hz: 60 dpi: 90 gamma: 1.2
    size: 473x296mm (18.62x11.65") diag: 558mm (22") ratio: 16:10 modes:
    max: 1680x1050 min: 720x400
  Monitor-2: DP-1 mapped: DisplayPort-0 pos: primary,bottom
    model: Acer K272HUL serial: <filter> built: 2018 res: 2560x1440 hz: 60
    dpi: 109 gamma: 1.2 size: 598x336mm (23.54x13.23") diag: 686mm (27")
    ratio: 16:9 modes: max: 2560x1440 min: 720x400
  API: EGL v: 1.5 hw: drv: amd radeonsi platforms: device: 0 drv: radeonsi
    device: 1 drv: swrast gbm: drv: radeonsi surfaceless: drv: radeonsi x11:
    drv: radeonsi inactive: wayland
  API: OpenGL v: 4.6 compat-v: 4.5 vendor: amd mesa v: 23.2.0-rc4 glx-v: 1.4
    direct-render: yes renderer: AMD Radeon R7 200 Series (oland LLVM 17.0.1
    DRM 3.52 6.4.12-1-default) device-ID: 1002:6611 memory: 1000 MiB
    unified: no
  API: Vulkan Message: No Vulkan data available.
#

Plasma session launches directly from XDM.