I’ve just checked my log. ~X11 reports Linux 4.19.92 even for me~. as @vcunat pointed out Current Operating System reports expected (5.4.22) version for me.
tail -1000 /var/log/X.0.log
[ 20495.762]
X.Org X Server 1.20.7
X Protocol Version 11, Revision 0
[ 20495.762] Build Operating System: Linux 4.19.92 x86_64
[ 20495.762] Current Operating System: Linux nixos-mainframe 5.4.22 #1-NixOS SMP Mon Feb 24 07:37:04 UTC 2020 x86_64
[ 20495.762] Kernel command line: initrd=\efi\nixos\zy76z4ziyv84d6idjvrvlwlm7c2gpihr-initrd-linux-5.4.22-initrd.efi systemConfig=/nix/store/dwzdj2p1lbrjpb0522j8dkqgv3ac40fz-nixos-system-nixos-mainframe-20.09pre214876.57f2ea5ca13 init=/nix/store/dwzdj2p1lbrjpb0522j8dkqgv3ac40fz-nixos-system-nixos-mainframe-20.09pre214876.57f2ea5ca13/init loglevel=4
[ 20495.762] Build Date: 13 January 2020 10:57:44PM
[ 20495.762]
[ 20495.762] Current version of pixman: 0.38.4
[ 20495.762] Before reporting problems, check http://wiki.x.org
to make sure that you have the latest version.
[ 20495.762] Markers: (--) probed, (**) from config file, (==) default setting,
(++) from command line, (!!) notice, (II) informational,
(WW) warning, (EE) error, (NI) not implemented, (??) unknown.
[ 20495.762] (++) Log file: "/var/log/X.0.log", Time: Mon Mar 16 16:08:58 2020
[ 20495.762] (++) Using config file: "/nix/store/mr0fnxgm3bsq0d361qncq02l762crhp1-xserver.conf"
[ 20495.762] (==) Using config directory: "/etc/X11/xorg.conf.d"
[ 20495.762] (==) Using system config directory "/nix/store/wa73k9mvspylka2c224waq626z4x4ss4-xorg-server-1.20.7/share/X11/xorg.conf.d"
[ 20495.762] (==) ServerLayout "Layout[all]"
[ 20495.762] (**) |-->Screen "Screen-amdgpu[0]" (0)
[ 20495.762] (**) | |-->Monitor "<default monitor>"
[ 20495.762] (**) | |-->Device "Device-amdgpu[0]"
[ 20495.762] (==) No monitor specified for screen "Screen-amdgpu[0]".
Using a default monitor configuration.
[ 20495.762] (**) Option "DontZap" "on"
[ 20495.763] (**) Option "AllowMouseOpenFail" "on"
[ 20495.763] (==) Automatically adding devices
[ 20495.763] (==) Automatically enabling devices
[ 20495.763] (==) Automatically adding GPU devices
[ 20495.763] (==) Max clients allowed: 256, resource mask: 0x1fffff
[ 20495.763] (**) FontPath set to:
/nix/store/qxnc5sxqncwihpwv7fd5hy0i3z8ij8hf-terminus-font-4.48/share/fonts/terminus,
/nix/store/59knwl4r4jyp1g76ai1n0gvdf469sq6a-font-bh-lucidatypewriter-100dpi-1.0.3/lib/X11/fonts/100dpi,
/nix/store/98pxfnc25r3a8c8v0hk6v9dkw7acnj3a-font-bh-lucidatypewriter-75dpi-1.0.3/lib/X11/fonts/75dpi,
/nix/store/a046qcgq89p7w4fsixyxwm75wq37hsr7-font-bh-100dpi-1.0.3/lib/X11/fonts/100dpi,
/nix/store/0i6zm5aiffwvm5kanm69kplg8lc493pv-font-misc-misc-1.1.2/lib/X11/fonts/misc,
/nix/store/j3k84ki5p04ixjacxnqrv7a3r2012n8y-font-cursor-misc-1.0.3/lib/X11/fonts/misc,
/nix/store/90mqaz34v73w6h5cw0q25b62cn9qbk3x-unifont-12.1.03/share/fonts,
/nix/store/vsygrz8bn4rxirnixi8j572d5spz1amr-font-adobe-100dpi-1.0.3/lib/X11/fonts/100dpi,
/nix/store/simkcqf29hlmav44v34mbb7h2akk9qxl-font-adobe-75dpi-1.0.3/lib/X11/fonts/75dpi
[ 20495.763] (**) ModulePath set to "/nix/store/hcdvxyzi1g1bx84cq46f4kwspmy40288-xf86-video-amdgpu-19.0.1/lib/xorg/modules/drivers,/nix/store/wa73k9mvspylka2c224waq626z4x4ss4-xorg-server-1.20.7/lib/xorg/modules,/nix/store/wa73k9mvspylka2c224waq626z4x4ss4-xorg-server-1.20.7/lib/xorg/modules/extensions,/nix/store/wa73k9mvspylka2c224waq626z4x4ss4-xorg-server-1.20.7/lib/xorg/modules/drivers,/nix/store/g9d68pdjy8ixfkwzcg1vkgvyc7rqsvzj-xf86-input-evdev-2.10.6/lib/xorg/modules/input"
[ 20495.763] (II) The server relies on udev to provide the list of input devices.
If no devices become available, reconfigure udev or disable AutoAddDevices.
[ 20495.763] (II) Loader magic: 0x625d40
[ 20495.763] (II) Module ABI versions:
[ 20495.763] X.Org ANSI C Emulation: 0.4
[ 20495.763] X.Org Video Driver: 24.1
[ 20495.763] X.Org XInput driver : 24.1
[ 20495.763] X.Org Server Extension : 10.0
[ 20495.763] (++) using VT number 7
[ 20495.763] (II) systemd-logind: logind integration requires -keeptty and -keeptty was not provided, disabling logind integration
[ 20495.764] (II) xfree86: Adding drm device (/dev/dri/card0)
[ 20495.769] (--) PCI:*(11@0:0:0) 1002:731f:1043:0577 rev 193, Mem @ 0xe0000000/268435456, 0xf0000000/2097152, 0xfcc00000/524288, I/O @ 0x0000e000/256, BIOS @ 0x????????/131072
[ 20495.769] (WW) Open ACPI failed (/var/run/acpid.socket) (No such file or directory)
[ 20495.769] (II) "glx" will be loaded by default.
[ 20495.769] (II) LoadModule: "dri2"
[ 20495.769] (II) Module "dri2" already built-in
[ 20495.769] (II) LoadModule: "glamoregl"
[ 20495.769] (II) Loading /nix/store/wa73k9mvspylka2c224waq626z4x4ss4-xorg-server-1.20.7/lib/xorg/modules/libglamoregl.so
[ 20495.771] (II) Module glamoregl: vendor="X.Org Foundation"
[ 20495.771] compiled for 1.20.7, module version = 1.0.1
[ 20495.772] ABI class: X.Org ANSI C Emulation, version 0.4
[ 20495.772] (II) LoadModule: "glx"
[ 20495.772] (II) Loading /nix/store/wa73k9mvspylka2c224waq626z4x4ss4-xorg-server-1.20.7/lib/xorg/modules/extensions/libglx.so
[ 20495.772] (II) Module glx: vendor="X.Org Foundation"
[ 20495.772] compiled for 1.20.7, module version = 1.0.0
[ 20495.772] ABI class: X.Org Server Extension, version 10.0
[ 20495.772] (II) LoadModule: "amdgpu"
[ 20495.772] (II) Loading /nix/store/hcdvxyzi1g1bx84cq46f4kwspmy40288-xf86-video-amdgpu-19.0.1/lib/xorg/modules/drivers/amdgpu_drv.so
[ 20495.772] (II) Module amdgpu: vendor="X.Org Foundation"
[ 20495.773] compiled for 1.20.7, module version = 19.0.1
[ 20495.773] Module class: X.Org Video Driver
[ 20495.773] ABI class: X.Org Video Driver, version 24.1
[ 20495.773] (II) AMDGPU: Driver for AMD Radeon:
All GPUs supported by the amdgpu kernel driver
[ 20495.773] (II) AMDGPU(0): [KMS] Kernel modesetting enabled.
[ 20495.773] (II) AMDGPU(0): Creating default Display subsection in Screen section
"Screen-amdgpu[0]" for depth/fbbpp 24/32
[ 20495.773] (==) AMDGPU(0): Depth 24, (--) framebuffer bpp 32
[ 20495.773] (II) AMDGPU(0): Pixel depth = 24 bits stored in 4 bytes (32 bpp pixmaps)
[ 20495.773] (==) AMDGPU(0): Default visual is TrueColor
[ 20495.773] (**) AMDGPU(0): Option "AccelMethod" "glamor"
[ 20495.773] (==) AMDGPU(0): RGB weight 888
[ 20495.773] (II) AMDGPU(0): Using 8 bits per RGB (8 bit DAC)
[ 20495.773] (--) AMDGPU(0): Chipset: "Unknown AMD Radeon GPU" (ChipID = 0x731f)
[ 20495.773] (II) Loading sub module "fb"
[ 20495.773] (II) LoadModule: "fb"
[ 20495.773] (II) Loading /nix/store/wa73k9mvspylka2c224waq626z4x4ss4-xorg-server-1.20.7/lib/xorg/modules/libfb.so
[ 20495.773] (II) Module fb: vendor="X.Org Foundation"
[ 20495.773] compiled for 1.20.7, module version = 1.0.0
[ 20495.773] ABI class: X.Org ANSI C Emulation, version 0.4
[ 20495.773] (II) Loading sub module "dri2"
[ 20495.773] (II) LoadModule: "dri2"
[ 20495.773] (II) Module "dri2" already built-in
[ 20495.827] (II) Loading sub module "glamoregl"
[ 20495.827] (II) LoadModule: "glamoregl"
[ 20495.827] (II) Loading /nix/store/wa73k9mvspylka2c224waq626z4x4ss4-xorg-server-1.20.7/lib/xorg/modules/libglamoregl.so
[ 20495.827] (II) Module glamoregl: vendor="X.Org Foundation"
[ 20495.827] compiled for 1.20.7, module version = 1.0.1
[ 20495.827] ABI class: X.Org ANSI C Emulation, version 0.4
[ 20495.840] (II) AMDGPU(0): glamor X acceleration enabled on AMD NAVI10 (DRM 3.35.0, 5.4.22, LLVM 9.0.1)
[ 20495.840] (II) AMDGPU(0): glamor detected, initialising EGL layer.
[ 20495.840] (==) AMDGPU(0): TearFree property default: auto
[ 20495.840] (==) AMDGPU(0): VariableRefresh: disabled
[ 20495.840] (II) AMDGPU(0): KMS Pageflipping: enabled
[ 20495.841] (II) AMDGPU(0): Output DisplayPort-0 has no monitor section
[ 20495.841] (II) AMDGPU(0): Output DisplayPort-1 has no monitor section
[ 20495.841] (II) AMDGPU(0): Output DisplayPort-2 has no monitor section
[ 20495.841] (II) AMDGPU(0): Output HDMI-A-0 has no monitor section
[ 20495.850] (II) AMDGPU(0): EDID for output DisplayPort-0
[ 20495.850] (II) AMDGPU(0): Manufacturer: GSM Model: 5b09 Serial#: 248551
[ 20495.850] (II) AMDGPU(0): Year: 2017 Week: 8
[ 20495.850] (II) AMDGPU(0): EDID Version: 1.4
[ 20495.850] (II) AMDGPU(0): Digital Display Input
[ 20495.850] (II) AMDGPU(0): 10 bits per channel
[ 20495.850] (II) AMDGPU(0): Digital interface is DisplayPort
[ 20495.850] (II) AMDGPU(0): Max Image Size [cm]: horiz.: 60 vert.: 34
[ 20495.850] (II) AMDGPU(0): Gamma: 2.20
[ 20495.850] (II) AMDGPU(0): DPMS capabilities: StandBy
[ 20495.850] (II) AMDGPU(0): Supported color encodings: RGB 4:4:4 YCrCb 4:4:4 YCrCb 4:2:2
[ 20495.850] (II) AMDGPU(0): Default color space is primary color space
[ 20495.850] (II) AMDGPU(0): First detailed timing is preferred mode
[ 20495.850] (II) AMDGPU(0): Preferred mode is native pixel format and refresh rate
[ 20495.850] (II) AMDGPU(0): redX: 0.652 redY: 0.335 greenX: 0.305 greenY: 0.637
[ 20495.850] (II) AMDGPU(0): blueX: 0.148 blueY: 0.062 whiteX: 0.313 whiteY: 0.329
[ 20495.850] (II) AMDGPU(0): Supported established timings:
[ 20495.850] (II) AMDGPU(0): 640x480@60Hz
[ 20495.850] (II) AMDGPU(0): 800x600@60Hz
[ 20495.850] (II) AMDGPU(0): 1024x768@60Hz
[ 20495.850] (II) AMDGPU(0): Manufacturer's mask: 0
[ 20495.850] (II) AMDGPU(0): Supported standard timings:
[ 20495.850] (II) AMDGPU(0): #0: hsize: 1152 vsize 864 refresh: 60 vid: 16497
[ 20495.850] (II) AMDGPU(0): #1: hsize: 1280 vsize 1024 refresh: 60 vid: 32897
[ 20495.850] (II) AMDGPU(0): #2: hsize: 1280 vsize 720 refresh: 60 vid: 49281
[ 20495.850] (II) AMDGPU(0): #3: hsize: 1600 vsize 900 refresh: 60 vid: 49321
[ 20495.850] (II) AMDGPU(0): #4: hsize: 1920 vsize 1080 refresh: 60 vid: 49361
[ 20495.850] (II) AMDGPU(0): #5: hsize: 1280 vsize 800 refresh: 60 vid: 129
[ 20495.850] (II) AMDGPU(0): Supported detailed timing:
[ 20495.850] (II) AMDGPU(0): clock: 533.2 MHz Image Size: 600 x 340 mm
[ 20495.850] (II) AMDGPU(0): h_active: 3840 h_sync: 3888 h_sync_end 3920 h_blank_end 4000 h_border: 0
[ 20495.850] (II) AMDGPU(0): v_active: 2160 v_sync: 2214 v_sync_end 2219 v_blanking: 2222 v_border: 0
[ 20495.850] (II) AMDGPU(0): Supported detailed timing:
[ 20495.850] (II) AMDGPU(0): clock: 266.6 MHz Image Size: 600 x 340 mm
[ 20495.850] (II) AMDGPU(0): h_active: 3840 h_sync: 3848 h_sync_end 3992 h_blank_end 4000 h_border: 0
[ 20495.850] (II) AMDGPU(0): v_active: 2160 v_sync: 2214 v_sync_end 2219 v_blanking: 2222 v_border: 0
[ 20495.850] (II) AMDGPU(0): Ranges: V min: 56 V max: 61 Hz, H min: 30 H max: 135 kHz, PixClock max 565 MHz
[ 20495.850] (II) AMDGPU(0): Monitor name: LG Ultra HD
[ 20495.850] (II) AMDGPU(0): Supported detailed timing:
[ 20495.850] (II) AMDGPU(0): clock: 148.5 MHz Image Size: 600 x 340 mm
[ 20495.850] (II) AMDGPU(0): h_active: 1920 h_sync: 2008 h_sync_end 2052 h_blank_end 2200 h_border: 0
[ 20495.850] (II) AMDGPU(0): v_active: 1080 v_sync: 1084 v_sync_end 1089 v_blanking: 1125 v_border: 0
[ 20495.850] (II) AMDGPU(0): Supported detailed timing:
[ 20495.850] (II) AMDGPU(0): clock: 241.5 MHz Image Size: 600 x 340 mm
[ 20495.850] (II) AMDGPU(0): h_active: 2560 h_sync: 2608 h_sync_end 2640 h_blank_end 2720 h_border: 0
[ 20495.850] (II) AMDGPU(0): v_active: 1440 v_sync: 1443 v_sync_end 1448 v_blanking: 1481 v_border: 0
[ 20495.850] (II) AMDGPU(0): Number of EDID sections to follow: 1
[ 20495.850] (II) AMDGPU(0): EDID (in hex):
[ 20495.850] (II) AMDGPU(0): 00ffffffffffff001e6d095be7ca0300
[ 20495.850] (II) AMDGPU(0): 081b0104b53c22789e3035a7554ea326
[ 20495.850] (II) AMDGPU(0): 0f50542108007140818081c0a9c0d1c0
[ 20495.850] (II) AMDGPU(0): 8100010101014dd000a0f0703e803020
[ 20495.850] (II) AMDGPU(0): 650c58542100001a286800a0f0703e80
[ 20495.850] (II) AMDGPU(0): 0890650c58542100001a000000fd0038
[ 20495.850] (II) AMDGPU(0): 3d1e8738000a202020202020000000fc
[ 20495.850] (II) AMDGPU(0): 004c4720556c7472612048440a2001e4
[ 20495.850] (II) AMDGPU(0): 02031171449004030123090707830100
[ 20495.850] (II) AMDGPU(0): 00023a801871382d40582c4500585421
[ 20495.850] (II) AMDGPU(0): 00001e565e00a0a0a029503020350058
[ 20495.850] (II) AMDGPU(0): 542100001a0000000000000000000000
[ 20495.850] (II) AMDGPU(0): 00000000000000000000000000000000
[ 20495.850] (II) AMDGPU(0): 00000000000000000000000000000000
[ 20495.850] (II) AMDGPU(0): 00000000000000000000000000000000
[ 20495.850] (II) AMDGPU(0): 000000000000000000000000000000c8
[ 20495.850] (II) AMDGPU(0): Printing probed modes for output DisplayPort-0
[ 20495.850] (II) AMDGPU(0): Modeline "3840x2160"x60.0 533.25 3840 3888 3920 4000 2160 2214 2219 2222 +hsync -vsync (133.3 kHz eP)
[ 20495.850] (II) AMDGPU(0): Modeline "3840x2160"x30.0 266.64 3840 3848 3992 4000 2160 2214 2219 2222 +hsync -vsync (66.7 kHz e)
[ 20495.850] (II) AMDGPU(0): Modeline "2560x1440"x60.0 241.50 2560 2608 2640 2720 1440 1443 1448 1481 +hsync -vsync (88.8 kHz e)
[ 20495.850] (II) AMDGPU(0): Modeline "1920x1200"x60.0 533.25 1920 3888 3920 4000 1200 2214 2219 2222 +hsync -vsync (133.3 kHz e)
[ 20495.850] (II) AMDGPU(0): Modeline "1920x1080"x60.0 148.50 1920 2008 2052 2200 1080 1084 1089 1125 +hsync +vsync (67.5 kHz e)
[ 20495.850] (II) AMDGPU(0): Modeline "1920x1080"x59.9 148.35 1920 2008 2052 2200 1080 1084 1089 1125 +hsync +vsync (67.4 kHz e)
[ 20495.850] (II) AMDGPU(0): Modeline "1600x1200"x60.0 533.25 1600 3888 3920 4000 1200 2214 2219 2222 +hsync -vsync (133.3 kHz e)
[ 20495.850] (II) AMDGPU(0): Modeline "1680x1050"x60.0 533.25 1680 3888 3920 4000 1050 2214 2219 2222 +hsync -vsync (133.3 kHz e)
[ 20495.850] (II) AMDGPU(0): Modeline "1600x900"x60.0 108.00 1600 1624 1704 1800 900 901 904 1000 +hsync +vsync (60.0 kHz e)
[ 20495.850] (II) AMDGPU(0): Modeline "1280x1024"x60.0 108.00 1280 1328 1440 1688 1024 1025 1028 1066 +hsync +vsync (64.0 kHz e)
[ 20495.850] (II) AMDGPU(0): Modeline "1440x900"x60.0 533.25 1440 3888 3920 4000 900 2214 2219 2222 +hsync -vsync (133.3 kHz e)
[ 20495.850] (II) AMDGPU(0): Modeline "1280x800"x59.8 83.50 1280 1352 1480 1680 800 803 809 831 -hsync +vsync (49.7 kHz e)
[ 20495.850] (II) AMDGPU(0): Modeline "1152x864"x60.0 81.58 1152 1216 1336 1520 864 865 868 895 -hsync +vsync (53.7 kHz)
[ 20495.850] (II) AMDGPU(0): Modeline "1280x720"x60.0 74.25 1280 1390 1430 1650 720 725 730 750 +hsync +vsync (45.0 kHz e)
[ 20495.850] (II) AMDGPU(0): Modeline "1280x720"x59.9 74.18 1280 1390 1430 1650 720 725 730 750 +hsync +vsync (45.0 kHz e)
[ 20495.850] (II) AMDGPU(0): Modeline "1024x768"x60.0 65.00 1024 1048 1184 1344 768 771 777 806 -hsync -vsync (48.4 kHz e)
[ 20495.850] (II) AMDGPU(0): Modeline "800x600"x60.3 40.00 800 840 968 1056 600 601 605 628 +hsync +vsync (37.9 kHz e)
[ 20495.850] (II) AMDGPU(0): Modeline "720x480"x60.0 27.03 720 736 798 858 480 489 495 525 -hsync -vsync (31.5 kHz e)
[ 20495.850] (II) AMDGPU(0): Modeline "720x480"x59.9 27.00 720 736 798 858 480 489 495 525 -hsync -vsync (31.5 kHz e)
[ 20495.850] (II) AMDGPU(0): Modeline "640x480"x60.0 25.20 640 656 752 800 480 490 492 525 -hsync -vsync (31.5 kHz e)
[ 20495.850] (II) AMDGPU(0): Modeline "640x480"x59.9 25.18 640 656 752 800 480 490 492 525 -hsync -vsync (31.5 kHz e)
[ 20495.850] (II) AMDGPU(0): EDID for output DisplayPort-1
[ 20495.850] (II) AMDGPU(0): EDID for output DisplayPort-2
[ 20495.850] (II) AMDGPU(0): EDID for output HDMI-A-0
[ 20495.850] (II) AMDGPU(0): Output DisplayPort-0 connected
[ 20495.850] (II) AMDGPU(0): Output DisplayPort-1 disconnected
[ 20495.850] (II) AMDGPU(0): Output DisplayPort-2 disconnected
[ 20495.850] (II) AMDGPU(0): Output HDMI-A-0 disconnected
[ 20495.850] (II) AMDGPU(0): Using exact sizes for initial modes
[ 20495.850] (II) AMDGPU(0): Output DisplayPort-0 using initial mode 3840x2160 +0+0
[ 20495.850] (II) AMDGPU(0): mem size init: gart size :1fe6ac000 vram size: s:1fc183000 visible:db91000
[ 20495.850] (++) AMDGPU(0): DPI set to (130, 130)
[ 20495.850] (==) AMDGPU(0): Using gamma correction (1.0, 1.0, 1.0)
[ 20495.850] (II) Loading sub module "ramdac"
[ 20495.850] (II) LoadModule: "ramdac"
[ 20495.850] (II) Module "ramdac" already built-in
[ 20495.851] (II) AMDGPU(0): [DRI2] Setup complete
[ 20495.851] (II) AMDGPU(0): [DRI2] DRI driver: radeonsi
[ 20495.851] (II) AMDGPU(0): [DRI2] VDPAU driver: radeonsi
[ 20495.851] (II) AMDGPU(0): Front buffer pitch: 15360 bytes
[ 20495.851] (II) AMDGPU(0): SYNC extension fences enabled
[ 20495.851] (II) AMDGPU(0): Present extension enabled
[ 20495.851] (==) AMDGPU(0): DRI3 enabled
[ 20495.851] (==) AMDGPU(0): Backing store enabled
[ 20495.851] (II) AMDGPU(0): Direct rendering enabled
[ 20495.857] (II) AMDGPU(0): Use GLAMOR acceleration.
[ 20495.857] (II) AMDGPU(0): Acceleration enabled
[ 20495.857] (==) AMDGPU(0): DPMS enabled
[ 20495.857] (==) AMDGPU(0): Silken mouse enabled
[ 20495.857] (II) AMDGPU(0): Set up textured video (glamor)
It seems to me that the important line for your issue is [ 20495.773] (II) AMDGPU(0): [KMS] Kernel modesetting enabled.
but I’m not and expert myself to be honest.