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flern

Member

Registered: 2023-10-29

Posts: 3

[SOLVED] USB C Monitor conn not working

I've checked as much as I can check, and googled as much as I can google in the forums. However, all the kings horses and all the kings men can't figure out how to get this display port over usb c to work.

Laptop: Lenovo Slim 7i

* Thunderbolt 4 on the left side (I can see a lil' thunderbolt icon)
* USB-C Altmode on the right side (total iconoclast)

dmsg

when I plug into either side:

[28054.479793] hub 3-4:1.0: USB hub found
[28054.482153] hub 3-4:1.0: 5 ports detected
[28054.764526] usb 3-4.5: new high-speed USB device number 19 using xhci_hcd
[28054.894085] usb 3-4.5: New USB device found, idVendor=0bda, idProduct=5418, bcdDevice= 1.01
[28054.894105] usb 3-4.5: New USB device strings: Mfr=17, Product=18, SerialNumber=19
[28054.894111] usb 3-4.5: Product: BillBoard Device
[28054.894116] usb 3-4.5: Manufacturer: Realtek
[28054.894120] usb 3-4.5: SerialNumber: 123456789ABCDEFGH

Monitor: Lenovo T32h-20

I'm plugged into the only USB-C slot, which also has the sign of a monitor next to it.

My compositor (niri) still only recognizes I have one monitor plugged in.

niri msg outputs
Output "eDP-1" (Unknown - Unknown - eDP-1)
  Current mode: 2560x1600 @ 60.001 Hz (preferred)
  Variable refresh rate: supported, disabled
  Physical size: 290x180 mm
  Logical position: 1280, 0
  Logical size: 1280x800
  Scale: 2
  Transform: normal
  Available modes:
    2560x1600@60.001 (current, preferred)
    2560x1600@90.001

What else should I try?

All the USB sysfs folders have no classes? I'm definitely doing power over usbc right now...

/sys/class/typec:

/sys/class/typec_mux:

/sys/class/usbmisc:

/sys/class/usb_power_delivery:

/sys/class/usb_role:

----

Things I've read:

* https://www.kernel.org/doc/html/v5.4/dr … c_bus.html
* https://bbs.archlinux.org/viewtopic.php?id=269272 (ls /sys/class/typec/ is empty)
* https://www.club-3d.com/en/technology/1 … _alt_mode/
* https://github.com/torvalds/linux/blob/ … playport.c (cool, but not useful)
* https://bbs.archlinux.org/viewtopic.php?id=274618 (nothing in typc for them either.)
* https://superuser.com/questions/1705769 … th-windows (when I figure this out...)

Last edited by flern (2024-06-19 20:01:24)

flern

Member

Registered: 2023-10-29

Posts: 3

Re: [SOLVED] USB C Monitor conn not working

It was the cable. I had to find a cable that specifically supported alt mode DP.

Someone on matrix helped me out :many-thanks: