That should make no difference.
Are there any *.conf files in 15.3’s /etc/X11/xorg.conf.d/ whose content could apply to graphics? This includes /etc/X11/xorg.conf if it exists. If yes, try moving them all elsewhere temporarily, then try restarting X or rebooting to see if it makes any difference.
The following result comes from 15.3 and a Radeon older than yours by several years. With no *.conf files in /etc/X11/xorg.conf.d/ applicable to display, neither amdgpu nor radeon, the following inexplicably results:
X won't start.
This is not to my recollection ever been normal behavior in Leap, or TW, or any other distro released in the past decade or so. Normally, automagic X configuration simply works for AMD’s and Intel’s GPUs. X should work normally with AMD and Intel GPUs when /etc/X11/xorg.conf.d/ doesn’t even exist.
However, if I include a .conf file that specifies either the modesetting DIX display driver, or the amdgpu DDX display driver, all is good:
# cat X11/xorg.conf.d/10-amdgpu.conf
Section "Device"
Identifier "AMDgpu"
# MatchDriver "amdgpu"
Driver "amdgpu"
EndSection
{(<[EOF]>)}
# inxi -GSaz --vs --za --hostname
inxi 3.3.35-00 (2024-06-18)
System:
Host: ara88 Kernel: 5.3.18-150300.59.106-default arch: x86_64 bits: 64
compiler: gcc v: 7.5.0 clocksource: tsc avail: hpet,acpi_pm
parameters: BOOT_IMAGE=/boot/vmlinuz root=LABEL=<filter> noresume
ipv6.disable=1 net.ifnames=0 radeon.cik_support=0 amdgpu.cik_support=1
consoleblank=0
Desktop: KDE Plasma v: 5.18.6 tk: Qt v: 5.12.7 info: frameworks v: 5.76.0
wm: kwin_x11 vt: 7 dm: 1: TDM 2: XDM Distro: openSUSE Leap 15.3
Graphics:
Device-1: AMD Kaveri [Radeon R7 Graphics] vendor: ASRock driver: amdgpu
v: kernel alternate: radeon arch: GCN-2 code: Sea Islands
process: GF/TSMC 16-28nm built: 2013-17 ports: active: DP-1,VGA-1
empty: DVI-D-1,HDMI-A-1 bus-ID: 00:01.0 chip-ID: 1002:130f class-ID: 0300
Display: x11 server: X.Org v: 1.20.3 compositor: kwin_x11 driver: X:
loaded: amdgpu unloaded: fbdev,modesetting,vesa dri: radeonsi gpu: amdgpu
display-ID: :0 screens: 1
Screen-1: 0 s-res: 2560x1440 s-dpi: 120 s-size: 541x304mm (21.30x11.97")
s-diag: 621mm (24.43")
Monitor-1: DP-1 mapped: DisplayPort-0 pos: primary 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
Monitor-2: VGA-1 mapped: VGA-0 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
API: OpenGL v: 4.6 vendor: x.org mesa v: 20.2.4 glx-v: 1.4 es-v: 3.2
direct-render: yes renderer: AMD KAVERI (DRM 3.39.0
5.3.18-150300.59.106-default LLVM 11.0.1) device-ID: 1002:130f
memory: 1000 MiB unified: no
#
# cat X11/xorg.conf.d/15-ddxdrv.conf
#Section "OutputClass"
Section "Device"
Identifier "DDX"
# MatchDriver "modesetting"
Driver "modesetting"
EndSection
{(<[EOF]>)}
# inxi -GSaz --vs --za --hostname
inxi 3.3.35-00 (2024-06-18)
System:
Host: ara88 Kernel: 5.3.18-150300.59.106-default arch: x86_64 bits: 64
compiler: gcc v: 7.5.0 clocksource: tsc avail: hpet,acpi_pm
parameters: BOOT_IMAGE=/boot/vmlinuz root=LABEL=<filter> noresume
ipv6.disable=1 net.ifnames=0 radeon.cik_support=0 amdgpu.cik_support=1
consoleblank=0
Desktop: KDE Plasma v: 5.18.6 tk: Qt v: 5.12.7 info: frameworks v: 5.76.0
wm: kwin_x11 vt: 7 dm: 1: TDM 2: XDM Distro: openSUSE Leap 15.3
Graphics:
Device-1: AMD Kaveri [Radeon R7 Graphics] vendor: ASRock driver: amdgpu
v: kernel alternate: radeon arch: GCN-2 code: Sea Islands
process: GF/TSMC 16-28nm built: 2013-17 ports: active: DP-1,VGA-1
empty: DVI-D-1,HDMI-A-1 bus-ID: 00:01.0 chip-ID: 1002:130f class-ID: 0300
Display: x11 server: X.Org v: 1.20.3 compositor: kwin_x11 driver: X:
loaded: modesetting dri: radeonsi gpu: amdgpu display-ID: :0 screens: 1
Screen-1: 0 s-res: 4240x1440 s-dpi: 120 s-size: 897x304mm (35.31x11.97")
s-diag: 947mm (37.29")
Monitor-1: DP-1 pos: right 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
Monitor-2: VGA-1 pos: primary,left 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
API: OpenGL v: 4.6 vendor: x.org mesa v: 20.2.4 glx-v: 1.4 es-v: 3.2
direct-render: yes renderer: AMD KAVERI (DRM 3.39.0
5.3.18-150300.59.106-default LLVM 11.0.1) device-ID: 1002:130f
memory: 1000 MiB unified: no
#
So, there may be a bug, and you do need an appropriate .conf file declaring which display driver to utilize. It may not matter which (amdgpu or modesetting), but it could be what’s happening is that X wants to fallback to the radeon driver by default, which I do not have installed, and is not a preferred display driver for AMD GPUs the age of mine or newer. Your inxi output shows 15.5 is using the modesetting DIX.