System boots to a black screen after a hard reset, goes away after removing the amdgpu-experimental package

Something very strange happened this morning which I’d like to get a better understanding of if possible. It occurred on my mother’s computer so what happened before I jumped in to investigate and fixed the problem is based on what she told me.

When she returned and moved the mouse, the screen wouldn’t come out of power saving. As I instructed her in case of any system freeze, she did a hard reset. But from this point on the screen would never turn back on even after a full restart: GRUB and the boot console would show up, but once the login screen was supposed to be displayed the monitor remained black. The screen didn’t go in power saving as if signal was lost, just printed the black color and nothing else. The machine wasn’t frozen either as I could toggle the NumLock keyboard LED and press the power button to shutdown gracefully.

I booted the Manjaro USB install drive and did a manjaro-chroot -a into the system. I was ultimately able to get rid of the issue by uninstalling the amdgpu-experimental package: I had that on because her graphics card is an old GCN 1.0 model, without it you only get the even more ancient radeon module instead of amdgpu. This indicates the issue would reside with its changes.

The weird thing though is that this worked fine for an year. No updates to anything like drivers or xorg or the kernel were preformed following this morning when it booted just fine: The OS doesn’t randomly modify its core display settings without either an update or a root command to do so, making it highly bizarre that permanent breakage persisting reboot would be introduced out of nowhere.

I’d like to understand what could have happened, since even on her machine I’d rather use amdgpu to have a proper driver so I’d like to put the experimental package back. All I have so far is the Xorg.0.log I extracted from the live session after the last failed boot… not seeing any errors explaining why X would crash before the login screen, I’m not that experienced so maybe I’m missing something.

[    10.541] (--) Log file renamed from "/var/log/Xorg.pid-814.log" to "/var/log/Xorg.0.log"
[    10.545] 
X.Org X Server 1.21.1.3
X Protocol Version 11, Revision 0
[    10.545] Current Operating System: Linux p5ql 5.16.2-1-MANJARO #1 SMP PREEMPT Thu Jan 20 17:33:11 CET 2022 x86_64
[    10.545] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-5.16-x86_64 root=UUID=fbeb3edb-db7c-4de4-abc4-5abe718ff4ce rw quiet apparmor=1 security=apparmor udev.log_priority=3
[    10.545]  
[    10.545] Current version of pixman: 0.40.0
[    10.545] 	Before reporting problems, check http://wiki.x.org
	to make sure that you have the latest version.
[    10.545] Markers: (--) probed, (**) from config file, (==) default setting,
	(++) from command line, (!!) notice, (II) informational,
	(WW) warning, (EE) error, (NI) not implemented, (??) unknown.
[    10.545] (==) Log file: "/var/log/Xorg.0.log", Time: Mon Jan 31 15:23:56 2022
[    10.550] (==) Using config directory: "/etc/X11/xorg.conf.d"
[    10.550] (==) Using system config directory "/usr/share/X11/xorg.conf.d"
[    10.552] (==) No Layout section.  Using the first Screen section.
[    10.552] (==) No screen section available. Using defaults.
[    10.552] (**) |-->Screen "Default Screen Section" (0)
[    10.552] (**) |   |-->Monitor "<default monitor>"
[    10.552] (==) No monitor specified for screen "Default Screen Section".
	Using a default monitor configuration.
[    10.552] (==) Automatically adding devices
[    10.552] (==) Automatically enabling devices
[    10.552] (==) Automatically adding GPU devices
[    10.552] (==) Automatically binding GPU devices
[    10.552] (==) Max clients allowed: 256, resource mask: 0x1fffff
[    10.554] (WW) The directory "/usr/share/fonts/OTF" does not exist.
[    10.554] 	Entry deleted from font path.
[    10.554] (WW) The directory "/usr/share/fonts/Type1" does not exist.
[    10.554] 	Entry deleted from font path.
[    10.554] (WW) The directory "/usr/share/fonts/100dpi" does not exist.
[    10.554] 	Entry deleted from font path.
[    10.554] (WW) The directory "/usr/share/fonts/75dpi" does not exist.
[    10.554] 	Entry deleted from font path.
[    10.554] (==) FontPath set to:
	/usr/share/fonts/misc,
	/usr/share/fonts/TTF
[    10.554] (==) ModulePath set to "/usr/lib/xorg/modules"
[    10.554] (II) The server relies on udev to provide the list of input devices.
	If no devices become available, reconfigure udev or disable AutoAddDevices.
[    10.554] (II) Module ABI versions:
[    10.554] 	X.Org ANSI C Emulation: 0.4
[    10.554] 	X.Org Video Driver: 25.2
[    10.554] 	X.Org XInput driver : 24.4
[    10.554] 	X.Org Server Extension : 10.0
[    10.555] (++) using VT number 1

[    10.555] (II) systemd-logind: logind integration requires -keeptty and -keeptty was not provided, disabling logind integration
[    10.557] (II) xfree86: Adding drm device (/dev/dri/card0)
[    10.557] (II) Platform probe for /sys/devices/pci0000:00/0000:00:01.0/0000:01:00.0/drm/card0
[    10.562] (--) PCI:*(1@0:0:0) 1002:6811:1458:2015 rev 129, Mem @ 0xd0000000/268435456, 0xfe880000/262144, I/O @ 0x0000b000/256, BIOS @ 0x????????/131072
[    10.562] (WW) Open ACPI failed (/var/run/acpid.socket) (No such file or directory)
[    10.563] (II) LoadModule: "glx"
[    10.569] (II) Loading /usr/lib/xorg/modules/extensions/libglx.so
[    10.580] (II) Module glx: vendor="X.Org Foundation"
[    10.580] 	compiled for 1.21.1.3, module version = 1.0.0
[    10.580] 	ABI class: X.Org Server Extension, version 10.0
[    10.580] (II) Applying OutputClass "AMDgpu" to /dev/dri/card0
[    10.580] 	loading driver: amdgpu
[    10.580] (==) Matched amdgpu as autoconfigured driver 0
[    10.581] (==) Matched ati as autoconfigured driver 1
[    10.581] (==) Matched modesetting as autoconfigured driver 2
[    10.581] (==) Matched fbdev as autoconfigured driver 3
[    10.581] (==) Matched vesa as autoconfigured driver 4
[    10.581] (==) Assigned the driver to the xf86ConfigLayout
[    10.581] (II) LoadModule: "amdgpu"
[    10.581] (II) Loading /usr/lib/xorg/modules/drivers/amdgpu_drv.so
[    10.589] (II) Module amdgpu: vendor="X.Org Foundation"
[    10.589] 	compiled for 1.21.1, module version = 21.0.0
[    10.589] 	Module class: X.Org Video Driver
[    10.589] 	ABI class: X.Org Video Driver, version 25.2
[    10.589] (II) LoadModule: "ati"
[    10.589] (II) Loading /usr/lib/xorg/modules/drivers/ati_drv.so
[    10.590] (II) Module ati: vendor="X.Org Foundation"
[    10.590] 	compiled for 1.21.1.1, module version = 19.1.0
[    10.590] 	Module class: X.Org Video Driver
[    10.590] 	ABI class: X.Org Video Driver, version 25.2
[    10.590] (II) LoadModule: "modesetting"
[    10.591] (II) Loading /usr/lib/xorg/modules/drivers/modesetting_drv.so
[    10.592] (II) Module modesetting: vendor="X.Org Foundation"
[    10.592] 	compiled for 1.21.1.3, module version = 1.21.1
[    10.592] 	Module class: X.Org Video Driver
[    10.592] 	ABI class: X.Org Video Driver, version 25.2
[    10.592] (II) LoadModule: "fbdev"
[    10.592] (WW) Warning, couldn't open module fbdev
[    10.592] (EE) Failed to load module "fbdev" (module does not exist, 0)
[    10.592] (II) LoadModule: "vesa"
[    10.592] (WW) Warning, couldn't open module vesa
[    10.592] (EE) Failed to load module "vesa" (module does not exist, 0)
[    10.592] (II) AMDGPU: Driver for AMD Radeon:
	All GPUs supported by the amdgpu kernel driver
[    10.592] (II) modesetting: Driver for Modesetting Kernel Drivers: kms
[    10.594] (WW) Falling back to old probe method for modesetting
[    10.595] (II) AMDGPU(0): Creating default Display subsection in Screen section
	"Default Screen Section" for depth/fbbpp 24/32
[    10.595] (==) AMDGPU(0): Depth 24, (--) framebuffer bpp 32
[    10.595] (II) AMDGPU(0): Pixel depth = 24 bits stored in 4 bytes (32 bpp pixmaps)
[    10.595] (==) AMDGPU(0): Default visual is TrueColor
[    10.595] (==) AMDGPU(0): RGB weight 888
[    10.595] (II) AMDGPU(0): Using 8 bits per RGB (8 bit DAC)
[    10.595] (--) AMDGPU(0): Chipset: "AMD Radeon R7 300 Series" (ChipID = 0x6811)
[    10.595] (II) Loading sub module "fb"
[    10.595] (II) LoadModule: "fb"
[    10.595] (II) Module "fb" already built-in
[    10.595] (II) Loading sub module "dri2"
[    10.595] (II) LoadModule: "dri2"
[    10.595] (II) Module "dri2" already built-in
[    10.933] (II) Loading sub module "glamoregl"
[    10.933] (II) LoadModule: "glamoregl"
[    10.933] (II) Loading /usr/lib/xorg/modules/libglamoregl.so
[    10.945] (II) Module glamoregl: vendor="X.Org Foundation"
[    10.945] 	compiled for 1.21.1.3, module version = 1.0.1
[    10.945] 	ABI class: X.Org ANSI C Emulation, version 0.4
[    10.980] (II) AMDGPU(0): glamor X acceleration enabled on AMD Radeon R7 300 Series (PITCAIRN, DRM 3.44.0, 5.16.2-1-MANJARO, LLVM 13.0.0)
[    10.980] (II) AMDGPU(0): glamor detected, initialising EGL layer.
[    10.980] (==) AMDGPU(0): TearFree property default: auto
[    10.980] (==) AMDGPU(0): VariableRefresh: disabled
[    10.980] (II) AMDGPU(0): KMS Pageflipping: enabled
[    10.980] (II) AMDGPU(0): Output DisplayPort-0 has no monitor section
[    10.980] (II) AMDGPU(0): Output HDMI-A-0 has no monitor section
[    10.980] (II) AMDGPU(0): Output DVI-D-0 has no monitor section
[    10.980] (II) AMDGPU(0): Output DVI-D-1 has no monitor section
[    10.981] (II) AMDGPU(0): EDID for output DisplayPort-0
[    10.981] (II) AMDGPU(0): EDID for output HDMI-A-0
[    10.981] (II) AMDGPU(0): EDID for output DVI-D-0
[    10.981] (II) AMDGPU(0): EDID for output DVI-D-1
[    10.981] (II) AMDGPU(0): Output DisplayPort-0 disconnected
[    10.981] (II) AMDGPU(0): Output HDMI-A-0 disconnected
[    10.981] (II) AMDGPU(0): Output DVI-D-0 disconnected
[    10.981] (II) AMDGPU(0): Output DVI-D-1 disconnected
[    10.981] (WW) AMDGPU(0): No outputs definitely connected, trying again...
[    10.981] (II) AMDGPU(0): Output DisplayPort-0 disconnected
[    10.981] (II) AMDGPU(0): Output HDMI-A-0 disconnected
[    10.981] (II) AMDGPU(0): Output DVI-D-0 disconnected
[    10.981] (II) AMDGPU(0): Output DVI-D-1 disconnected
[    10.981] (WW) AMDGPU(0): Unable to find connected outputs - setting 1024x768 initial framebuffer
[    10.981] (II) AMDGPU(0): mem size init: gart size :bfce3000 vram size: s:7f341000 visible:1032a000
[    10.981] (==) AMDGPU(0): DPI set to (96, 96)
[    10.981] (==) AMDGPU(0): Using gamma correction (1.0, 1.0, 1.0)
[    10.981] (II) Loading sub module "ramdac"
[    10.981] (II) LoadModule: "ramdac"
[    10.981] (II) Module "ramdac" already built-in
[    10.981] (II) UnloadModule: "modesetting"
[    10.981] (II) Unloading modesetting
[    10.981] (II) AMDGPU(0): [DRI2] Setup complete
[    10.981] (II) AMDGPU(0): [DRI2]   DRI driver: radeonsi
[    10.981] (II) AMDGPU(0): [DRI2]   VDPAU driver: radeonsi
[    10.982] (II) AMDGPU(0): Front buffer pitch: 4096 bytes
[    10.985] (II) AMDGPU(0): SYNC extension fences enabled
[    10.985] (II) AMDGPU(0): Present extension enabled
[    10.985] (==) AMDGPU(0): DRI3 enabled
[    10.985] (==) AMDGPU(0): Backing store enabled
[    10.985] (II) AMDGPU(0): Direct rendering enabled
[    11.028] (II) AMDGPU(0): Use GLAMOR acceleration.
[    11.028] (II) AMDGPU(0): Acceleration enabled
[    11.028] (==) AMDGPU(0): DPMS enabled
[    11.028] (==) AMDGPU(0): Silken mouse enabled
[    11.028] (II) AMDGPU(0): Set up textured video (glamor)
[    11.033] (II) Initializing extension Generic Event Extension
[    11.033] (II) Initializing extension SHAPE
[    11.033] (II) Initializing extension MIT-SHM
[    11.033] (II) Initializing extension XInputExtension
[    11.034] (II) Initializing extension XTEST
[    11.034] (II) Initializing extension BIG-REQUESTS
[    11.034] (II) Initializing extension SYNC
[    11.034] (II) Initializing extension XKEYBOARD
[    11.035] (II) Initializing extension XC-MISC
[    11.035] (II) Initializing extension SECURITY
[    11.035] (II) Initializing extension XFIXES
[    11.035] (II) Initializing extension RENDER
[    11.035] (II) Initializing extension RANDR
[    11.036] (II) Initializing extension COMPOSITE
[    11.036] (II) Initializing extension DAMAGE
[    11.036] (II) Initializing extension MIT-SCREEN-SAVER
[    11.036] (II) Initializing extension DOUBLE-BUFFER
[    11.036] (II) Initializing extension RECORD
[    11.037] (II) Initializing extension DPMS
[    11.037] (II) Initializing extension Present
[    11.037] (II) Initializing extension DRI3
[    11.037] (II) Initializing extension X-Resource
[    11.037] (II) Initializing extension XVideo
[    11.038] (II) Initializing extension XVideo-MotionCompensation
[    11.038] (II) Initializing extension GLX
[    11.047] (II) AIGLX: Loaded and initialized radeonsi
[    11.047] (II) GLX: Initialized DRI2 GL provider for screen 0
[    11.047] (II) Initializing extension XFree86-VidModeExtension
[    11.047] (II) Initializing extension XFree86-DGA
[    11.047] (II) Initializing extension XFree86-DRI
[    11.047] (II) Initializing extension DRI2
[    11.287] (II) config/udev: Adding input device Power Button (/dev/input/event1)
[    11.287] (**) Power Button: Applying InputClass "evdev keyboard catchall"
[    11.287] (**) Power Button: Applying InputClass "libinput keyboard catchall"
[    11.287] (**) Power Button: Applying InputClass "system-keyboard"
[    11.287] (II) LoadModule: "libinput"
[    11.287] (II) Loading /usr/lib/xorg/modules/input/libinput_drv.so
[    11.293] (II) Module libinput: vendor="X.Org Foundation"
[    11.293] 	compiled for 1.21.1, module version = 1.2.0
[    11.293] 	Module class: X.Org XInput Driver
[    11.293] 	ABI class: X.Org XInput driver, version 24.4
[    11.293] (II) Using input driver 'libinput' for 'Power Button'
[    11.293] (**) Power Button: always reports core events
[    11.293] (**) Option "Device" "/dev/input/event1"
[    11.294] (**) Option "_source" "server/udev"
[    11.309] (II) event1  - Power Button: is tagged by udev as: Keyboard
[    11.309] (II) event1  - Power Button: device is a keyboard
[    11.309] (II) event1  - Power Button: device removed
[    11.334] (**) Option "config_info" "udev:/sys/devices/LNXSYSTM:00/LNXPWRBN:00/input/input1/event1"
[    11.334] (II) XINPUT: Adding extended input device "Power Button" (type: KEYBOARD, id 6)
[    11.334] (**) Option "xkb_layout" "us"
[    11.336] (II) event1  - Power Button: is tagged by udev as: Keyboard
[    11.336] (II) event1  - Power Button: device is a keyboard
[    11.338] (II) config/udev: Adding input device Power Button (/dev/input/event0)
[    11.338] (**) Power Button: Applying InputClass "evdev keyboard catchall"
[    11.338] (**) Power Button: Applying InputClass "libinput keyboard catchall"
[    11.338] (**) Power Button: Applying InputClass "system-keyboard"
[    11.338] (II) Using input driver 'libinput' for 'Power Button'
[    11.338] (**) Power Button: always reports core events
[    11.338] (**) Option "Device" "/dev/input/event0"
[    11.338] (**) Option "_source" "server/udev"
[    11.340] (II) event0  - Power Button: is tagged by udev as: Keyboard
[    11.340] (II) event0  - Power Button: device is a keyboard
[    11.340] (II) event0  - Power Button: device removed
[    11.371] (**) Option "config_info" "udev:/sys/devices/LNXSYSTM:00/LNXSYBUS:00/PNP0C0C:00/input/input0/event0"
[    11.371] (II) XINPUT: Adding extended input device "Power Button" (type: KEYBOARD, id 7)
[    11.371] (**) Option "xkb_layout" "us"
[    11.372] (II) event0  - Power Button: is tagged by udev as: Keyboard
[    11.372] (II) event0  - Power Button: device is a keyboard
[    11.374] (II) config/udev: Adding input device HDA ATI HDMI HDMI/DP,pcm=9 (/dev/input/event10)
[    11.374] (II) No input driver specified, ignoring this device.
[    11.374] (II) This device may have been added with another device file.
[    11.374] (II) config/udev: Adding input device HDA ATI HDMI HDMI/DP,pcm=10 (/dev/input/event11)
[    11.374] (II) No input driver specified, ignoring this device.
[    11.374] (II) This device may have been added with another device file.
[    11.375] (II) config/udev: Adding input device HDA ATI HDMI HDMI/DP,pcm=11 (/dev/input/event12)
[    11.375] (II) No input driver specified, ignoring this device.
[    11.375] (II) This device may have been added with another device file.
[    11.376] (II) config/udev: Adding input device HDA ATI HDMI HDMI/DP,pcm=3 (/dev/input/event7)
[    11.376] (II) No input driver specified, ignoring this device.
[    11.376] (II) This device may have been added with another device file.
[    11.376] (II) config/udev: Adding input device HDA ATI HDMI HDMI/DP,pcm=7 (/dev/input/event8)
[    11.376] (II) No input driver specified, ignoring this device.
[    11.376] (II) This device may have been added with another device file.
[    11.377] (II) config/udev: Adding input device HDA ATI HDMI HDMI/DP,pcm=8 (/dev/input/event9)
[    11.377] (II) No input driver specified, ignoring this device.
[    11.377] (II) This device may have been added with another device file.
[    11.377] (II) config/udev: Adding input device HDA Intel Front Mic (/dev/input/event13)
[    11.377] (II) No input driver specified, ignoring this device.
[    11.377] (II) This device may have been added with another device file.
[    11.378] (II) config/udev: Adding input device HDA Intel Rear Mic (/dev/input/event14)
[    11.378] (II) No input driver specified, ignoring this device.
[    11.378] (II) This device may have been added with another device file.
[    11.379] (II) config/udev: Adding input device HDA Intel Line (/dev/input/event15)
[    11.379] (II) No input driver specified, ignoring this device.
[    11.379] (II) This device may have been added with another device file.
[    11.379] (II) config/udev: Adding input device HDA Intel Line Out Front (/dev/input/event16)
[    11.379] (II) No input driver specified, ignoring this device.
[    11.379] (II) This device may have been added with another device file.
[    11.380] (II) config/udev: Adding input device HDA Intel Line Out Surround (/dev/input/event17)
[    11.380] (II) No input driver specified, ignoring this device.
[    11.380] (II) This device may have been added with another device file.
[    11.380] (II) config/udev: Adding input device HDA Intel Line Out CLFE (/dev/input/event18)
[    11.380] (II) No input driver specified, ignoring this device.
[    11.380] (II) This device may have been added with another device file.
[    11.382] (II) config/udev: Adding input device HDA Intel Line Out Side (/dev/input/event19)
[    11.382] (II) No input driver specified, ignoring this device.
[    11.382] (II) This device may have been added with another device file.
[    11.383] (II) config/udev: Adding input device HDA Intel Front Headphone (/dev/input/event20)
[    11.383] (II) No input driver specified, ignoring this device.
[    11.383] (II) This device may have been added with another device file.
[    11.386] (II) config/udev: Adding input device DELL DELL USB Laser Mouse (/dev/input/event2)
[    11.386] (**) DELL DELL USB Laser Mouse: Applying InputClass "evdev pointer catchall"
[    11.386] (**) DELL DELL USB Laser Mouse: Applying InputClass "libinput pointer catchall"
[    11.386] (II) Using input driver 'libinput' for 'DELL DELL USB Laser Mouse'
[    11.386] (**) DELL DELL USB Laser Mouse: always reports core events
[    11.386] (**) Option "Device" "/dev/input/event2"
[    11.386] (**) Option "_source" "server/udev"
[    11.442] (II) event2  - DELL DELL USB Laser Mouse: is tagged by udev as: Mouse
[    11.443] (II) event2  - DELL DELL USB Laser Mouse: device set to 1000 DPI
[    11.443] (II) event2  - DELL DELL USB Laser Mouse: device is a pointer
[    11.443] (II) event2  - DELL DELL USB Laser Mouse: device removed
[    11.487] (**) Option "config_info" "udev:/sys/devices/pci0000:00/0000:00:1d.2/usb8/8-1/8-1:1.0/0003:046D:C063.0001/input/input2/event2"
[    11.487] (II) XINPUT: Adding extended input device "DELL DELL USB Laser Mouse" (type: MOUSE, id 8)
[    11.488] (**) Option "AccelerationScheme" "none"
[    11.488] (**) DELL DELL USB Laser Mouse: (accel) selected scheme none/0
[    11.488] (**) DELL DELL USB Laser Mouse: (accel) acceleration factor: 2.000
[    11.488] (**) DELL DELL USB Laser Mouse: (accel) acceleration threshold: 4
[    11.548] (II) event2  - DELL DELL USB Laser Mouse: is tagged by udev as: Mouse
[    11.548] (II) event2  - DELL DELL USB Laser Mouse: device set to 1000 DPI
[    11.548] (II) event2  - DELL DELL USB Laser Mouse: device is a pointer
[    11.551] (II) config/udev: Adding input device DELL DELL USB Laser Mouse (/dev/input/mouse0)
[    11.551] (II) No input driver specified, ignoring this device.
[    11.551] (II) This device may have been added with another device file.
[    11.553] (II) config/udev: Adding input device SEM USB Keyboard (/dev/input/event3)
[    11.554] (**) SEM USB Keyboard: Applying InputClass "evdev keyboard catchall"
[    11.554] (**) SEM USB Keyboard: Applying InputClass "libinput keyboard catchall"
[    11.554] (**) SEM USB Keyboard: Applying InputClass "system-keyboard"
[    11.554] (II) Using input driver 'libinput' for 'SEM USB Keyboard'
[    11.554] (**) SEM USB Keyboard: always reports core events
[    11.554] (**) Option "Device" "/dev/input/event3"
[    11.554] (**) Option "_source" "server/udev"
[    11.557] (II) event3  - SEM USB Keyboard: is tagged by udev as: Keyboard
[    11.557] (II) event3  - SEM USB Keyboard: device is a keyboard
[    11.558] (II) event3  - SEM USB Keyboard: device removed
[    11.584] (**) Option "config_info" "udev:/sys/devices/pci0000:00/0000:00:1d.2/usb8/8-2/8-2:1.0/0003:1A2C:0E24.0002/input/input3/event3"
[    11.584] (II) XINPUT: Adding extended input device "SEM USB Keyboard" (type: KEYBOARD, id 9)
[    11.584] (**) Option "xkb_layout" "us"
[    11.589] (II) event3  - SEM USB Keyboard: is tagged by udev as: Keyboard
[    11.589] (II) event3  - SEM USB Keyboard: device is a keyboard
[    11.592] (II) config/udev: Adding input device SEM USB Keyboard Consumer Control (/dev/input/event4)
[    11.592] (**) SEM USB Keyboard Consumer Control: Applying InputClass "evdev keyboard catchall"
[    11.592] (**) SEM USB Keyboard Consumer Control: Applying InputClass "libinput keyboard catchall"
[    11.592] (**) SEM USB Keyboard Consumer Control: Applying InputClass "system-keyboard"
[    11.592] (II) Using input driver 'libinput' for 'SEM USB Keyboard Consumer Control'
[    11.593] (**) SEM USB Keyboard Consumer Control: always reports core events
[    11.593] (**) Option "Device" "/dev/input/event4"
[    11.593] (**) Option "_source" "server/udev"
[    11.596] (II) event4  - SEM USB Keyboard Consumer Control: is tagged by udev as: Keyboard
[    11.596] (II) event4  - SEM USB Keyboard Consumer Control: device is a keyboard
[    11.597] (II) event4  - SEM USB Keyboard Consumer Control: device removed
[    11.611] (II) libinput: SEM USB Keyboard Consumer Control: needs a virtual subdevice
[    11.611] (**) Option "config_info" "udev:/sys/devices/pci0000:00/0000:00:1d.2/usb8/8-2/8-2:1.1/0003:1A2C:0E24.0003/input/input4/event4"
[    11.611] (II) XINPUT: Adding extended input device "SEM USB Keyboard Consumer Control" (type: MOUSE, id 10)
[    11.611] (**) Option "AccelerationScheme" "none"
[    11.611] (**) SEM USB Keyboard Consumer Control: (accel) selected scheme none/0
[    11.611] (**) SEM USB Keyboard Consumer Control: (accel) acceleration factor: 2.000
[    11.611] (**) SEM USB Keyboard Consumer Control: (accel) acceleration threshold: 4
[    11.615] (II) event4  - SEM USB Keyboard Consumer Control: is tagged by udev as: Keyboard
[    11.616] (II) event4  - SEM USB Keyboard Consumer Control: device is a keyboard
[    11.619] (II) config/udev: Adding input device SEM USB Keyboard System Control (/dev/input/event5)
[    11.619] (**) SEM USB Keyboard System Control: Applying InputClass "evdev keyboard catchall"
[    11.619] (**) SEM USB Keyboard System Control: Applying InputClass "libinput keyboard catchall"
[    11.619] (**) SEM USB Keyboard System Control: Applying InputClass "system-keyboard"
[    11.619] (II) Using input driver 'libinput' for 'SEM USB Keyboard System Control'
[    11.619] (**) SEM USB Keyboard System Control: always reports core events
[    11.619] (**) Option "Device" "/dev/input/event5"
[    11.619] (**) Option "_source" "server/udev"
[    11.623] (II) event5  - SEM USB Keyboard System Control: is tagged by udev as: Keyboard
[    11.624] (II) event5  - SEM USB Keyboard System Control: device is a keyboard
[    11.624] (II) event5  - SEM USB Keyboard System Control: device removed
[    11.657] (**) Option "config_info" "udev:/sys/devices/pci0000:00/0000:00:1d.2/usb8/8-2/8-2:1.1/0003:1A2C:0E24.0003/input/input5/event5"
[    11.657] (II) XINPUT: Adding extended input device "SEM USB Keyboard System Control" (type: KEYBOARD, id 11)
[    11.657] (**) Option "xkb_layout" "us"
[    11.661] (II) event5  - SEM USB Keyboard System Control: is tagged by udev as: Keyboard
[    11.661] (II) event5  - SEM USB Keyboard System Control: device is a keyboard
[    11.663] (II) config/udev: Adding input device PC Speaker (/dev/input/event6)
[    11.663] (II) No input driver specified, ignoring this device.
[    11.663] (II) This device may have been added with another device file.
[    11.683] (**) SEM USB Keyboard Consumer Control: Applying InputClass "evdev keyboard catchall"
[    11.683] (**) SEM USB Keyboard Consumer Control: Applying InputClass "libinput keyboard catchall"
[    11.683] (**) SEM USB Keyboard Consumer Control: Applying InputClass "system-keyboard"
[    11.683] (II) Using input driver 'libinput' for 'SEM USB Keyboard Consumer Control'
[    11.683] (**) SEM USB Keyboard Consumer Control: always reports core events
[    11.683] (**) Option "Device" "/dev/input/event4"
[    11.683] (**) Option "_source" "_driver/libinput"
[    11.683] (II) libinput: SEM USB Keyboard Consumer Control: is a virtual subdevice
[    11.683] (**) Option "config_info" "udev:/sys/devices/pci0000:00/0000:00:1d.2/usb8/8-2/8-2:1.1/0003:1A2C:0E24.0003/input/input4/event4"
[    11.683] (II) XINPUT: Adding extended input device "SEM USB Keyboard Consumer Control" (type: KEYBOARD, id 12)
[    11.683] (**) Option "xkb_layout" "us"
[    41.782] (II) event1  - Power Button: device removed
[    41.788] (II) event0  - Power Button: device removed
[    41.824] (II) event2  - DELL DELL USB Laser Mouse: device removed
[    41.851] (II) event3  - SEM USB Keyboard: device removed
[    41.864] (II) event5  - SEM USB Keyboard System Control: device removed
[    41.871] (II) event4  - SEM USB Keyboard Consumer Control: device removed
[    41.892] (II) UnloadModule: "libinput"
[    41.892] (II) UnloadModule: "libinput"
[    41.892] (II) UnloadModule: "libinput"
[    41.892] (II) UnloadModule: "libinput"
[    41.892] (II) UnloadModule: "libinput"
[    41.892] (II) UnloadModule: "libinput"
[    41.893] (II) UnloadModule: "libinput"
[    41.898] (II) Server terminated successfully (0). Closing log file.

Gentle shut down a suddenly hanged PC to minimize a chance of getting a broken filesystem and data loss:

You can get all sorts of issues by performing a hard reset, or a power down. This is dependent on the used filesystem. There are filesystems, that will not break easily. These are filesystems that perform CoW

see

Btrfs

https://wiki.manjaro.org/index.php/Btrfs

True. I always try do a clean shutdown whenever possible, biggest issue there is typically power outages. All of our drives use ext4 at that. This doesn’t seem like a case of data corruption per say, if that was the case I’d likely have even bigger issues with that machine now: It’s like Xorg or similar broke after the system crashed, but I’m not sure what could have made changes to their configuration.

From time to time the DE does save config files. When interrupted in between … the new file is not ready and the old file is already gone.

This can be as easy as removing / replacing a config file.

In my system i would have looked what files did change in this time-frame. Or no, i would do a easy rollback to the time before the corruption.
This is the reason btrfs exists, and snapper, and other solutions that do make snapshots and allow to rollback. If you can rollback, there is no reason to search WHY it happend. Because even if it happens again, it will not bother you.

No. Even ext4 uses a log, and protects most of your filesystem this way. But it cant protect what was on the way to be written.

Just a proposition, if it is your mother’s computer without extraordinary hardware and which I suppose is used for casual/trivial things, there’s no reason it to be running on latest kernel, I’d say stick with LTS kernels and you will have far less headaches, for example kernel 5.16.x had/(still has?) problems with waking up from sleep.

Update: I reinstalled the amdgpu-experimental package and everything works fine once more after restarting. I can only presume a config got broken when the system crashed, reconfiguring GRUB and the kernel from the rescue session must have then fixed it.

Her computer may have frozen because of a memory leak in Firefox: We’ve had that for over an year on that machine, with only 8 GB of RAM she had to restart FF periodically. The leak has been absent nowadays but I suspect it could still be there and happening at times.