USB C port no longer able to output to external monitor

General system Kernel, boot, graphics & hardware
21

Thank you for your help.

Also, for completeness. The output plugging the usb c to HDMI adapter into the problematic port:

Nov 11 00:37:41 sf-latitude kernel: usb 3-2: new low-speed USB device number 25 using xhci_hcd
Nov 11 00:37:42 sf-latitude kernel: usb 3-2: No LPM exit latency info found, disabling LPM.
Nov 11 00:37:42 sf-latitude kernel: usb 3-2: New USB device found, idVendor=343c, idProduct=0000, bcdDevice= 0.00
Nov 11 00:37:42 sf-latitude kernel: usb 3-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
Nov 11 00:37:42 sf-latitude kernel: usb 3-2: Product: USB Type-C Digital AV Adapter
Nov 11 00:37:42 sf-latitude kernel: usb 3-2: Manufacturer: xxxxxxxx
Nov 11 00:37:42 sf-latitude kernel: usb 3-2: SerialNumber: 000000000000

And the output from plugging that cable into the non-problematic port:

Nov 11 00:39:49 sf-latitude kernel: usb 3-1: new low-speed USB device number 26 using xhci_hcd
Nov 11 00:39:49 sf-latitude systemd[1]: Rotate log files was skipped because of an unmet condition check (ConditionACPower=true).
Nov 11 00:39:49 sf-latitude kernel: usb 3-1: No LPM exit latency info found, disabling LPM.
Nov 11 00:39:49 sf-latitude kernel: usb 3-1: New USB device found, idVendor=343c, idProduct=0000, bcdDevice= 0.00
Nov 11 00:39:49 sf-latitude kernel: usb 3-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
Nov 11 00:39:49 sf-latitude kernel: usb 3-1: Product: USB Type-C Digital AV Adapter
Nov 11 00:39:49 sf-latitude kernel: usb 3-1: Manufacturer: xxxxxxxx
Nov 11 00:39:49 sf-latitude kernel: usb 3-1: SerialNumber: 000000000000
Nov 11 00:39:50 sf-latitude niri[1995]: 2025-11-11T05:39:50.700973Z DEBUG niri::backend::tty: device changed: 57857
Nov 11 00:39:50 sf-latitude niri[1995]: 2025-11-11T05:39:50.778997Z DEBUG niri::backend::tty: new connector: DP-1 "PanaScope Pixio PX248P 0x00000001"
Nov 11 00:39:50 sf-latitude niri[1995]: 2025-11-11T05:39:50.779066Z DEBUG niri::backend::tty: connecting connector: DP-1
Nov 11 00:39:50 sf-latitude niri[1995]: 2025-11-11T05:39:50.779082Z DEBUG niri::backend::tty: picking mode: Mode { name: "1920x1080", clock: 148500, size: (1920, 1080), hsync: (2008, 2052, 2200), vsync: (1084, 1089, 1125), hskew: 0, vscan: 0, vrefresh: 60, mode_type: ModeTypeFlags(PREFERRED | DRIVER) }
Nov 11 00:39:50 sf-latitude niri[1995]: 2025-11-11T05:39:50.783029Z DEBUG niri::niri: putting output DP-1 at x=3286 y=0
22

you should post the results of
inxi -Faz

This to me suggest that maybe the plug is now set as a power device :man_shrugging:

23

Sure, was there a specific section you would want? This is the Graphics sections while the usb c to displayport cable is plugged into the problematic port

Graphics:
  Device-1: Intel Alder Lake-UP3 GT2 [Iris Xe Graphics] vendor: Dell
    driver: i915 v: kernel alternate: xe arch: Xe process: Intel 10nm
    built: 2021-22+ ports: active: eDP-1 empty: DP-1,DP-2,HDMI-A-1
    bus-ID: 00:02.0 chip-ID: 8086:46a8 class-ID: 0300
  Device-2: Bizlink DisplayPort ALT mode device driver: N/A type: USB
    rev: 2.0 speed: 12 Mb/s lanes: 1 mode: 1.1 bus-ID: 3-2:31 chip-ID: 06c4:c100
    class-ID: 1100
  Device-3: Realtek Integrated_Webcam_HD driver: uvcvideo type: USB rev: 2.0
    speed: 480 Mb/s lanes: 1 mode: 2.0 bus-ID: 3-6:3 chip-ID: 0bda:554a
    class-ID: fe01 serial: <filter>
  Display: wayland server: X.org v: 1.21.1.20 with: Xwayland v: 24.1.9
    compositor: niri driver: gpu: i915 display-ID: 1
  Monitor-1: eDP-1 model: ChiMei InnoLux 0x1500 built: 2018 res: 1366x768
    dpi: 101 gamma: 1.2 size: 344x193mm (13.54x7.6") diag: 394mm (15.5")
    ratio: 16:9 modes: 1366x768
  API: EGL v: 1.5 hw: drv: intel iris platforms: device: 0 drv: iris
    device: 1 drv: swrast gbm: drv: iris surfaceless: drv: iris wayland:
    drv: iris x11: drv: iris
  API: OpenGL v: 4.6 compat-v: 4.5 vendor: intel mesa v: 25.2.6-arch1.1
    glx-v: 1.4 direct-render: yes renderer: Mesa Intel Iris Xe Graphics (ADL
    GT2) device-ID: 8086:46a8 memory: 30.3 GiB unified: yes
  Info: Tools: api: eglinfo,glxinfo wl: swaymsg,wlr-randr
    x11: xdpyinfo, xprop, xrandr

It seems to show up as Device-2

And here is the output when the same cable is plugged into the non-problematic port:

Graphics:
  Device-1: Intel Alder Lake-UP3 GT2 [Iris Xe Graphics] vendor: Dell
    driver: i915 v: kernel alternate: xe arch: Xe process: Intel 10nm
    built: 2021-22+ ports: active: DP-1,eDP-1 empty: DP-2,HDMI-A-1
    bus-ID: 00:02.0 chip-ID: 8086:46a8 class-ID: 0300
  Device-2: Realtek Integrated_Webcam_HD driver: uvcvideo type: USB rev: 2.0
    speed: 480 Mb/s lanes: 1 mode: 2.0 bus-ID: 3-6:3 chip-ID: 0bda:554a
    class-ID: fe01 serial: <filter>
  Display: wayland server: X.org v: 1.21.1.20 with: Xwayland v: 24.1.9
    compositor: niri driver: gpu: i915 display-ID: 1
  Monitor-1: DP-1 model: Pixio PX248P serial: <filter> built: 2020
    res: 1920x1080 dpi: 92 gamma: 1.2 size: 526x296mm (20.71x11.65")
    diag: 604mm (23.8") ratio: 16:9 modes: max: 1920x1080 min: 720x400
  Monitor-2: eDP-1 model: ChiMei InnoLux 0x1500 built: 2018 res: 1366x768
    dpi: 101 gamma: 1.2 size: 344x193mm (13.54x7.6") diag: 394mm (15.5")
    ratio: 16:9 modes: 1366x768
  API: EGL v: 1.5 hw: drv: intel iris platforms: device: 0 drv: iris
    device: 1 drv: swrast gbm: drv: iris surfaceless: drv: iris wayland:
    drv: iris x11: drv: iris
  API: OpenGL v: 4.6 compat-v: 4.5 vendor: intel mesa v: 25.2.6-arch1.1
    glx-v: 1.4 direct-render: yes renderer: Mesa Intel Iris Xe Graphics (ADL
    GT2) device-ID: 8086:46a8 memory: 30.3 GiB unified: yes
  Info: Tools: api: eglinfo,glxinfo wl: swaymsg,wlr-randr
    x11: xdpyinfo, xprop, xrandr
24

just checking as can rule out things, have you tried to use i3, openbox etc? I usally have one or other just in case. they will be barebones but handy to riule things out.

25

Not yet, I actually only have wayland compositors installed, but I will try other WM/DEs now and see if anything changes. Though, normally when I boot into my laptop the TTY displays on both monitors and now it only displays on the laptop when using the troublesome port

26

So this did work, kind of, thank you smokey! I say kind of because I am unsure of what exactly changed to solve the issue, or if the issue will remain resolved, but I will detail what I did in steps that led to the usb port working for displays again. I will include things that are likely not important since I am unsure of what is actually important.

Starting point: I am in a niri session with my external monitor connected via a functioning hdmi port built into the laptop.

  1. Edit the default .xinitrc to start openbox. Changing the last line from exec “$xterm” -geometry 80x66+0+0 -name login to exec openbox-session
  2. Exit niri into the tty
  3. Install openbox
  4. Enter startx in the tty
  5. Openbox starts and is displayed on both monitors
  6. Remove the HDMI cable and plug the usb c to displayport cable into the problematic port
  7. The external monitor goes black and enters sleep mode
  8. Logout of the openbox session back to the tty
  9. The external monitor comes back on and is now mirroring the display

From then on the cable and port have functioned as they used to. I have unplugged the cable and plugged it back in and it works the same. I have also restarted the laptop and it functions as expected. If the issue comes up again soon I will come back to this thread (if that is what standard practice is).

Thanks to everyone who spent their time helping me. I am unsure of what is considered good manners on this forum so for now I will mark this post as the solution in case anyone stumbles upon a similar issue. Please let me know if this is improper.