Monitor does not get a signal via USB-C (DP)

Hello all

I have a Medion notebook E4253 and a Dell monitor U2720Q. The notebook has a USB-C with DisplayPort port and I would like to use the Dell monitor with it. But unfortunately I get no signal when I connect the USB-C cable that comes with the monitor. The monitor also has an integrated HUB, which is recognized by the operating system without a problem as soon as I connect the notebook with the USB-C cable.

lspci | grep VGA
VGA compatible controller: Intel Corporation GeminiLake [UHD Graphics 605] (rev 03)

lscpu | grep -E ‘(odel|amily)’
Intel(R) Pentium(R) Silver N5000 CPU @ 1.10GHz

lsusb without connected USB-C cabel
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 004: ID 8087:0aaa Intel Corp. Bluetooth 9460/9560 Jefferson Peak (JfP)
Bus 001 Device 003: ID 058f:3822 Alcor Micro Corp. USB 2.0 Camera
Bus 001 Device 002: ID 0bda:0129 Realtek Semiconductor Corp. RTS5129 Card Reader Controller
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

lsusb with connected USB-C cabel
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 004: ID 8087:0aaa Intel Corp. Bluetooth 9460/9560 Jefferson Peak (JfP)
Bus 001 Device 003: ID 058f:3822 Alcor Micro Corp. USB 2.0 Camera
Bus 001 Device 002: ID 0bda:0129 Realtek Semiconductor Corp. RTS5129 Card Reader Controller
Bus 001 Device 016: ID 0451:82ff Texas Instruments, Inc.
Bus 001 Device 015: ID 0451:8442 Texas Instruments, Inc.
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

The window manager is wayland.

Currently, after much google, I unfortunately do not know what to do and I could not fix the problem. I would rule out a defect in the cable and monitor, since I still have a MacBook and here everything works plug & play.

I am very grateful for your help
Many greetings

1 Like

The window manager is wayland.

Does it work on X?

Unfortunately no. Changing the window manager to X was the first thing I tried.

Hi,

With the USB-C cable connected, whats the output of usb-devices ?

Thanks Tom.

Can you try, at the Monitor end, disable auto detect of input source by manually setting input to usb-c port?

Sometimes when both ends are auto detecting, the end result is not the best.

@tjdoyle here is the output:
T: Bus=01 Lev=00 Prnt=00 Port=00 Cnt=00 Dev#= 1 Spd=480 MxCh= 9
D: Ver= 2.00 Cls=09(hub ) Sub=00 Prot=01 MxPS=64 #Cfgs= 1
P: Vendor=1d6b ProdID=0002 Rev=05.11
S: Manufacturer=Linux 5.11.10-200.fc33.x86_64 xhci-hcd
S: Product=xHCI Host Controller
S: SerialNumber=0000:00:15.0
C: #Ifs= 1 Cfg#= 1 Atr=e0 MxPwr=0mA
I: If#=0x0 Alt= 0 #EPs= 1 Cls=09(hub ) Sub=00 Prot=00 Driver=hub

T: Bus=01 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#= 21 Spd=480 MxCh= 6
D: Ver= 2.10 Cls=09(hub ) Sub=00 Prot=02 MxPS=64 #Cfgs= 1
P: Vendor=0451 ProdID=8442 Rev=01.00
S: SerialNumber=B701008983CB
C: #Ifs= 1 Cfg#= 1 Atr=e0 MxPwr=0mA
I: If#=0x0 Alt= 1 #EPs= 1 Cls=09(hub ) Sub=00 Prot=02 Driver=hub

T: Bus=01 Lev=02 Prnt=21 Port=04 Cnt=01 Dev#= 22 Spd=480 MxCh= 0
D: Ver= 2.01 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs= 1
P: Vendor=0451 ProdID=82ff Rev=02.00
C: #Ifs= 1 Cfg#= 1 Atr=c0 MxPwr=0mA
I: If#=0x0 Alt= 0 #EPs= 1 Cls=03(HID ) Sub=00 Prot=00 Driver=usbhid

T: Bus=01 Lev=01 Prnt=01 Port=02 Cnt=02 Dev#= 2 Spd=480 MxCh= 0
D: Ver= 2.00 Cls=ff(vend.) Sub=ff Prot=ff MxPS=64 #Cfgs= 1
P: Vendor=0bda ProdID=0129 Rev=39.60
S: Manufacturer=Generic
S: Product=USB2.0-CRW
S: SerialNumber=20100201396000000
C: #Ifs= 1 Cfg#= 1 Atr=a0 MxPwr=500mA
I: If#=0x0 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=06 Prot=50 Driver=rtsx_usb

T: Bus=01 Lev=01 Prnt=01 Port=05 Cnt=03 Dev#= 3 Spd=480 MxCh= 0
D: Ver= 2.00 Cls=ef(misc ) Sub=02 Prot=01 MxPS=64 #Cfgs= 1
P: Vendor=058f ProdID=3822 Rev=06.00
S: Product=USB 2.0 Camera
C: #Ifs= 2 Cfg#= 1 Atr=80 MxPwr=200mA
I: If#=0x0 Alt= 0 #EPs= 1 Cls=0e(video) Sub=01 Prot=00 Driver=uvcvideo
I: If#=0x1 Alt= 0 #EPs= 0 Cls=0e(video) Sub=02 Prot=00 Driver=uvcvideo

T: Bus=01 Lev=01 Prnt=01 Port=08 Cnt=04 Dev#= 4 Spd=12 MxCh= 0
D: Ver= 2.00 Cls=e0(wlcon) Sub=01 Prot=01 MxPS=64 #Cfgs= 1
P: Vendor=8087 ProdID=0aaa Rev=00.02
C: #Ifs= 2 Cfg#= 1 Atr=e0 MxPwr=100mA
I: If#=0x0 Alt= 0 #EPs= 3 Cls=e0(wlcon) Sub=01 Prot=01 Driver=btusb
I: If#=0x1 Alt= 0 #EPs= 2 Cls=e0(wlcon) Sub=01 Prot=01 Driver=btusb

T: Bus=02 Lev=00 Prnt=00 Port=00 Cnt=00 Dev#= 1 Spd=5000 MxCh= 7
D: Ver= 3.00 Cls=09(hub ) Sub=00 Prot=03 MxPS= 9 #Cfgs= 1
P: Vendor=1d6b ProdID=0003 Rev=05.11
S: Manufacturer=Linux 5.11.10-200.fc33.x86_64 xhci-hcd
S: Product=xHCI Host Controller
S: SerialNumber=0000:00:15.0
C: #Ifs= 1 Cfg#= 1 Atr=e0 MxPwr=0mA
I: If#=0x0 Alt= 0 #EPs= 1 Cls=09(hub ) Sub=00 Prot=00 Driver=hub

@SampsonF I have turned off auto detect, but without success

1 Like

If you have a type-C to display port adapter on hand to test with, it should help further to isolate if it is a hardware of software issue.

Sometimes system Firmware are controlling the functions of multi-function ports. Please do check the System Firmware settings and if firmware updates are available or not.

Hi,

Doesn’t look like the display is being detected, only reporting the hub & and an input device. Maybe easier to use via the display port.

Thanks Tom.

@tjdoyle @SampsonF

A little update on this issue:
I have now ordered a USB-C to DisplayPort cable. After trying it out, I have now unfortunately encountered another problem.

  1. if I plug in the cable while the computer is running, both screens go black. If I unplug the cable again, then the screen of the notebook remains black and I have to restart the notebook via the power button to geht ist back working.
  2. If the cable is plugged in during the boot process, everything works fine - only the integrated hub is not recognized. But, I don’t care about that for now.

One more thing: I read again in the specifications of the notebook. It says that a second display via the USB-C port only works with a corresponding USB-C to DisplayPort adapter. My original issue is a hardware problem and not a problem with Linux or Fedora! :relaxed:

1 Like

So with a USB-C to DP cable, it works with cold plug but not with hot plug.

It indicates the firmware & driver combination is not mature enough.

Strange, when I test Fedora as a live system, connecting the screen also works while the system is running (hot plug)

1 Like

Try install the same version of kernel of the LiveCD to your installed Fedora Linux and see if it helps.

1 Like

Ok, it really seems to be a kernel problem. With the currently installed kernel 5.11.14-200.fc33.x86_64 hot plug does not work — only soft plug. If I change to kernel 5.8.15-301.fc33.x86_64 soft and hot plug is working

1 Like

If you file a bug report about this regression, it will help the kernel team to fix this issue.

I faced similar issues as you and found this thread. I have a Dell DA310 USB-C Dock, on which the monitor wasn’t detected over Displayport, even on Windows.

For me the solution was to pull the power plug of the display, effectively rebooting it.

Perhaps worth a shot for you too. I have observed on several displays that the powersaving features over Displayport are unreliable (e.g. screen stays blank instead of going to standby), so this may very well help you too.

Necro post on a thread that has been dead for more than 2 years.
Closing.