F43 KDE plasma - external monitor USB-C failure after disconnection

Hello all

Amazed at the loveliness of fedora 43 KDE Plasma when I had to recover a failed Windows laptop and just decided to dodge Win11 and finally make the desktop jump after many years of using unix/linux professionally.

All has been super easy and mostly Just Worked with the exception of my external Dell C2722DE which has an intermittent issue, similar but not quite the same as a few others on the forum - the laptop is a HP Elitebook G5.

I am using USB-C for power, ethernet and video successfully until I detach the laptop to move elsewhere - when I return and plug in again I get the “No USB C signal” message on the Dell and it goes into sleep mode. It will not see the laptop again until I reboot - at which point all is well again.

I don’t see much on the Dell site about linux for this device except references to some old firmware - my Dell is running M3T113 which seems pretty current. I don’t see anything in the journal or elsewhere - I would love some suggestions as to how to approach this. Laptop deets below.

inxi -Fxpmrz                                                                                                                                                                                                                                                                                                                                                                 
System:                                                                                                                                                                                                                                                                                                                                                                      
  Kernel: 6.18.7-200.fc43.x86_64 arch: x86_64 bits: 64 compiler: gcc v: 15.2.1                                                                                                                                                                                                                                                                                               
  Desktop: KDE Plasma v: 6.5.5 Distro: Fedora Linux 43 (KDE Plasma Desktop                                                                                                                                                                                                                                                                                                   
    Edition)                                                                                                                                                                                                                                                                                                                                                                 
Machine:                                                                                                                                                                                                                                                                                                                                                                     
  Type: Laptop System: HP product: HP EliteBook 840 G5 v: SBKPF                                                                                                                                                                                                                                                                                                              
    serial: <superuser required>                                                                                                                                                                                                                                                                                                                                             
  Mobo: HP model: 83B2 v: KBC Version 04.70.00 serial: <superuser required>                                                                                                                                                                                                                                                                                                  
    Firmware: UEFI vendor: HP v: Q78 Ver. 01.31.00 date: 03/10/2025                                                                                                                                                                                                                                                                                                          
Battery:                                                                                                                                                                                                                                                                                                                                                                     
  ID-1: BAT0 charge: 30.5 Wh (94.5%) condition: 32.3/50 Wh (64.6%)                                                                                                                                                                                                                                                                                                           
    volts: 12.16 min: 11.55 model: Hewlett-Packard Primary status: not charging                                                                                                                                                                                                                                                                                              
  Device-1: hidpp_battery_0 model: Logitech Wireless Mouse                                                                                                                                                                                                                                                                                                                   
    charge: 50% (should be ignored) status: N/A                                                                                                                                                                                                                                                                                                                              
Memory:                                                                                                                                                                                                                                                                                                                                                                      
  System RAM: total: 16 GiB available: 14.99 GiB used: 8.07 GiB (53.8%)                                                                                                                                                                                                                                                                                                      
  Array-1: capacity: 32 GiB slots: 2 modules: 2 EC: None                                                                                                                                                                                                                                                                                                                     
    max-module-size: 16 GiB note: est.                                                                                                                                                                                                                                                                                                                                       
  Device-1: Bottom-Slot 1(left) type: DDR4 size: 8 GiB speed: 2400 MT/s                                                                                                                                                                                                                                                                                                      
  Device-2: Bottom-Slot 2(right) type: DDR4 size: 8 GiB speed: 2400 MT/s                                                                                                                                                                                                                                                                                                     
CPU:                                                                                                                                                                                                                                                                                                                                                                         
  Info: quad core model: Intel Core i5-8350U bits: 64 type: MT MCP                                                                                                                                                                                                                                                                                                           
    arch: Coffee Lake rev: A cache: L1: 256 KiB L2: 1024 KiB L3: 6 MiB                                                                                                                                                                                                                                                                                                       
  Speed (MHz): avg: 800 min/max: 400/3600 cores: 1: 800 2: 800 3: 800 4: 800                                                                                                                                                                                                                                                                                                 
    5: 800 6: 800 7: 800 8: 800 bogomips: 30399                                                                                                                                                                                                                                                                                                                              
  Flags-basic: avx avx2 ht lm nx pae sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx                                                                                                                                                                                                                                                                                                   
Graphics:                                                                                                                                                                                                                                                                                                                                                                    
  Device-1: Intel Kaby Lake-R GT2 [UHD Graphics 620] vendor: Hewlett-Packard                                                                                                                                                                                                                                                                                                 
    driver: i915 v: kernel arch: Gen-9.5 bus-ID: 00:02.0                                                                                                                                                                                                                                                                                                                     
  Device-2: Cheng Uei Precision Industry (Foxlink) Webcam driver: uvcvideo                                                                                                                                                                                                                                                                                                   
    type: USB bus-ID: 1-9:9                                                                                                                                                                                                                                                                                                                                                  
  Display: wayland server: Xwayland v: 24.1.9 compositor: kwin_wayland                                                                                                                                                                                                                                                                                                       
    driver: gpu: i915 resolution: 1: 2560x1440~60Hz 2: 1920x1080~60Hz                                                                                                                                                                                                                                                                                                        
  API: EGL v: 1.5 drivers: iris,swrast platforms:                                                                                                                                                                                                                                                                                                                            
    active: gbm,wayland,x11,surfaceless,device inactive: N/A                                                                                                                                                                                                                                                                                                                 
  API: OpenGL v: 4.6 compat-v: 4.5 vendor: intel mesa v: 25.2.7 glx-v: 1.4                                                                                                                                                                                                                                                                                                   
    direct-render: yes renderer: Mesa Intel UHD Graphics 620 (KBL GT2)                                                                                                                                                                                                                                                                                                       
  API: Vulkan v: 1.4.328 drivers: intel,llvmpipe surfaces: N/A devices: 2                                                                                                                                                                                                                                                                                                    
  Info: Tools: api: clinfo, eglinfo, glxinfo, vulkaninfo                                                                                                                                                                                                                                                                                                                     
    de: kscreen-console,kscreen-doctor wl: wayland-info x11: xdriinfo,                                                                                                                                                                                                                                                                                                       
    xdpyinfo, xprop, xrandr
Audio:                                                                                                                                                                                                                                                                                                                                                                       
  Device-1: Intel Sunrise Point-LP HD Audio vendor: Hewlett-Packard                                                                                                                                                                                                                                                                                                          
    driver: snd_hda_intel v: kernel bus-ID: 00:1f.3                                                                                                                                                                                                                                                                                                                          
  Device-2: Dell C2722DE driver: hid-generic,snd-usb-audio,usbhid type: USB                                                                                                                                                                                                                                                                                                  
    bus-ID: 1-5.3:14                                                                                                                                                                                                                                                                                                                                                         
  API: ALSA v: k6.18.7-200.fc43.x86_64 status: kernel-api                                                                                                                                                                                                                                                                                                                    
  Server-1: PipeWire v: 1.4.10 status: active                                                                                                                                                                                                                                                                                                                                
Network:                                                                                                                                                                                                                                                                                                                                                                     
  Device-1: Intel Ethernet I219-LM vendor: Hewlett-Packard driver: e1000e                                                                                                                                                                                                                                                                                                    
    v: kernel port: N/A bus-ID: 00:1f.6                                                                                                                                                                                                                                                                                                                                      
  IF: enp0s31f6 state: down mac: <filter>                                                                                                                                                                                                                                                                                                                                    
  Device-2: Intel Wireless 8265 / 8275 driver: iwlwifi v: kernel                                                                                                                                                                                                                                                                                                             
    bus-ID: 01:00.0                                                                                                                                                                                                                                                                                                                                                          
  IF: wlp1s0 state: down mac: <filter>                                                                                                                                                                                                                                                                                                                                       
  Device-3: Realtek RTL8153 Gigabit Ethernet Adapter driver: r8152 type: USB                                                                                                                                                                                                                                                                                                 
    bus-ID: 4-1.2:4                                                                                                                                                                                                                                                                                                                                                          
  IF: enp58s0u1u2 state: up speed: 100 Mbps duplex: full mac: <filter>                                                                                                                                                                                                                                                                                                       
  IF-ID-1: prd-azure state: unknown speed: N/A duplex: N/A mac: N/A                                                                                                                                                                                                                                                                                                          
  IF-ID-2: prdadm-new state: unknown speed: N/A duplex: N/A mac: N/A                                                                                                                                                                                                                                                                                                         
  IF-ID-3: staging-azure state: unknown speed: N/A duplex: N/A mac: N/A                                                                                                                                                                                                                                                                                                      
  IF-ID-4: tstadm-new state: unknown speed: N/A duplex: N/A mac: N/A                                                                                                                                                                                                                                                                                                         
  IF-ID-5: tstadm-pedi state: unknown speed: N/A duplex: N/A mac: N/A                                                                                                                                                                                                                                                                                                        
Bluetooth:                                                                                                                                                                                                                                                                                                                                                                   
  Device-1: Intel Bluetooth wireless interface driver: btusb v: 0.8 type: USB                                                                                                                                                                                                                                                                                                
    bus-ID: 1-7:7                                                                                                                                                                                                                                                                                                                                                            
  Report: btmgmt ID: hci0 rfk-id: 0 state: up address: <filter> bt-v: 4.2                                                                                                                                                                                                                                                                                                    
    lmp-v: 8                                                                                                                                                                                                                                                                                                                                                                                                
Swap:                                                                                                                                                                                                                                                                                                                                                                        
  ID-1: swap-1 type: zram size: 8 GiB used: 0 KiB (0.0%) dev: /dev/zram0                                                                                                                                                                                                                                                                                                     
Sensors:                                                                                                                                                                                                                                                                                                                                                                     
  System Temperatures: cpu: 60.0 C pch: 43.5 C mobo: N/A                                                                                                                                                                                                                                                                                                                     
  Fan Speeds (rpm): N/A                                                                                                                                                                                                                                                                                                                                                      
...                                                                                                                                                                                                                                                                                                         
  Compilers: gcc: 15.2.1 Shell: Bash v: 5.3.0 inxi: 3.3.40    

Fixed this myself - the following:

sudo ddcutil -v usbenv

seems to trawl the USB devices and has the effect of reactivating my external screen. HTH.