Not detecting second screen

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1

I have an Asus Zenbook flip S (UX-370UAR, Intel Core i7-8550U CPU). It has two USB-C ports and both work well.

Windows detects perfectly and automatically when I connect a second screen (using HDMI and an USB-C dongle), so shows both screens.

Ubuntu does not usually detect the second screen. The screen is not even receiving any signal via the HDMI. However, sometimes, after a few restarts with the screen connected, it manage to turn the second screen on and everything works fine. This usually lasts after I disconnect the USB-C to move the laptop.

This has been happening since Ubuntu 18.04 and I have tried 20.04 and now 24.04.

Hope I can finally get this issue solved with your help

Best!

Ubuntu Version:

  • 24.04 LTS

Relevant System Information:

  • sudo lshw -C display
       description: VGA compatible controller
       product: UHD Graphics 620
       vendor: Intel Corporation
       physical id: 2
       bus info: pci@0000:00:02.0
       logical name: /dev/fb0
       version: 07
       width: 64 bits
       clock: 33MHz
       capabilities: pciexpress msi pm vga_controller bus_master cap_list rom fb
       configuration: depth=32 driver=i915 latency=0 resolution=1920,1080
       resources: irq:141 memory:ee000000-eeffffff memory:d0000000-dfffffff ioport:f000(size=64) memory:c0000-dffff
  • uname -a
Linux vks-asus 6.8.0-51-generic #52-Ubuntu SMP PREEMPT_DYNAMIC Thu Dec  5 13:09:44 UTC 2024 x86_64 x86_64 x86_64 GNU/Linux
2

Start the computer without the display connected, and run xrandr, and capture the output.

Also, in another terminal run sudo dmesg -Tw.

Then connect the USB C cable, and run xrandr again, is there any difference to the output? Can you paste both outputs here?
What appears in the dmesg window?

3

Thanks for the answer.

The output of xrandr is the same:

Screen 0: minimum 16 x 16, current 1920 x 1080, maximum 32767 x 32767
eDP-1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 290mm x 170mm
   1920x1080     59.96*+
   1440x1080     59.99  
   1400x1050     59.98  
   1280x1024     59.89  
   1280x960      59.94  
   1152x864      59.96  
   1024x768      59.92  
   800x600       59.86  
   640x480       59.38  
   320x240       59.52  
   1680x1050     59.95  
   1440x900      60.03  
   1280x800      59.99  
   1152x720      59.97  
   960x600       59.96  
   928x580       59.88  
   800x500       59.50  
   768x480       59.90  
   720x480       59.71  
   640x400       59.95  
   320x200       58.96  
   1600x900      59.95  
   1368x768      59.88  
   1280x720      59.86  
   1024x576      59.90  
   864x486       59.92  
   720x400       59.55  
   640x350       59.77

The output of dmesg is huge. I do not see anything pointing out there. What do you want to check there?

Thanks!

4

You don’t need to paste the whole output of dmesg, only what appears at the point when you plug the USB C cable in, and onwards. It may contain information regarding what’s going wrong. The -Tw option means that it will “tail” the dmesg output and print timestamps. So you know when the messages appeared.

5

Thanks for the answer,

Here is what changed after connecting the USB-C hub with the HDMI.

[Wed Jan 22 13:56:48 2025] usb 1-1: new high-speed USB device number 25 using xhci_hcd
[Wed Jan 22 13:56:48 2025] usb 1-1: New USB device found, idVendor=xx, idProduct=xx, bcdDevice= xx
[Wed Jan 22 13:56:48 2025] usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=xx
[Wed Jan 22 13:56:48 2025] usb 1-1: Product: USB2.0 Hub
[Wed Jan 22 13:56:48 2025] usb 1-1: Manufacturer: VIA Labs, Inc.
[Wed Jan 22 13:56:48 2025] hub 1-1:1.0: USB hub found
[Wed Jan 22 13:56:48 2025] hub 1-1:1.0: 4 ports detected
[Wed Jan 22 13:56:48 2025] usb 2-1: new SuperSpeed USB device number 18 using xhci_hcd
[Wed Jan 22 13:56:48 2025] usb 2-1: New USB device found, idVendor=xx, idProduct=xx, bcdDevice= xx
[Wed Jan 22 13:56:48 2025] usb 2-1: New USB device strings: Mfr=1, Product=2, SerialNumber=xx
[Wed Jan 22 13:56:48 2025] usb 2-1: Product: USB3.0 Hub
[Wed Jan 22 13:56:48 2025] usb 2-1: Manufacturer: VIA Labs, Inc.
[Wed Jan 22 13:56:48 2025] hub 2-1:1.0: USB hub found
[Wed Jan 22 13:56:48 2025] hub 2-1:1.0: 4 ports detected
[Wed Jan 22 13:56:49 2025] usb 1-1.4: new high-speed USB device number 26 using xhci_hcd
[Wed Jan 22 13:56:49 2025] usb 1-1.4: New USB device found, idVendor=xx, idProduct=xx, bcdDevice= xx
[Wed Jan 22 13:56:49 2025] usb 1-1.4: New USB device strings: Mfr=1, Product=2, SerialNumber=xx
[Wed Jan 22 13:56:49 2025] usb 1-1.4: Product: USB2.0 Hub
[Wed Jan 22 13:56:49 2025] usb 1-1.4: Manufacturer: VIA Labs, Inc.
[Wed Jan 22 13:56:49 2025] hub 1-1.4:1.0: USB hub found
[Wed Jan 22 13:56:49 2025] hub 1-1.4:1.0: 4 ports detected
[Wed Jan 22 13:56:49 2025] usb 2-1.4: new SuperSpeed USB device number 19 using xhci_hcd
[Wed Jan 22 13:56:49 2025] usb 2-1.4: New USB device found, idVendor=xx, idProduct=xx, bcdDevice= xx
[Wed Jan 22 13:56:49 2025] usb 2-1.4: New USB device strings: Mfr=1, Product=2, SerialNumber=xx
[Wed Jan 22 13:56:49 2025] usb 2-1.4: Product: USB3.0 Hub
[Wed Jan 22 13:56:49 2025] usb 2-1.4: Manufacturer: VIA Labs, Inc.
[Wed Jan 22 13:56:49 2025] hub 2-1.4:1.0: USB hub found
[Wed Jan 22 13:56:49 2025] hub 2-1.4:1.0: 4 ports detected
[Wed Jan 22 13:56:50 2025] usb 2-1.4.4: new SuperSpeed USB device number 20 using xhci_hcd
[Wed Jan 22 13:56:50 2025] usb 2-1.4.4: New USB device found, idVendor=xx, idProduct=xx, bcdDevice=xx
[Wed Jan 22 13:56:50 2025] usb 2-1.4.4: New USB device strings: Mfr=3, Product=4, SerialNumber=xx
[Wed Jan 22 13:56:50 2025] usb 2-1.4.4: Product: USB3.0 Card Reader
[Wed Jan 22 13:56:50 2025] usb 2-1.4.4: Manufacturer: Generic
[Wed Jan 22 13:56:50 2025] usb 2-1.4.4: SerialNumber: xxx
[Wed Jan 22 13:56:50 2025] usb-storage 2-1.4.4:1.0: USB Mass Storage device detected
[Wed Jan 22 13:56:50 2025] scsi host3: usb-storage 2-1.4.4:1.0
[Wed Jan 22 13:56:50 2025] usb 1-1.4.3: new high-speed USB device number xx using xhci_hcd
[Wed Jan 22 13:56:50 2025] usb 1-1.4.3: New USB device found, idVendor=xx, idProduct=xx, bcdDevice= xx
[Wed Jan 22 13:56:50 2025] usb 1-1.4.3: New USB device strings: Mfr=1, Product=2, SerialNumber=xx
[Wed Jan 22 13:56:50 2025] usb 1-1.4.3: Product: USB 2.0 BILLBOARD             
[Wed Jan 22 13:56:50 2025] usb 1-1.4.3: Manufacturer: VIA Technologies Inc.         
[Wed Jan 22 13:56:50 2025] usb 1-1.4.3: SerialNumber: xxx
[Wed Jan 22 13:56:51 2025] usb 2-1.4.1: new SuperSpeed USB device number 21 using xhci_hcd
[Wed Jan 22 13:56:51 2025] usb 2-1.4.1: New USB device found, idVendor=xx, idProduct=xx, bcdDevice=xx
[Wed Jan 22 13:56:51 2025] usb 2-1.4.1: New USB device strings: Mfr=1, Product=2, SerialNumber=xx
[Wed Jan 22 13:56:51 2025] usb 2-1.4.1: Product: USB 10/100/1000 LAN
[Wed Jan 22 13:56:51 2025] usb 2-1.4.1: Manufacturer: Realtek
[Wed Jan 22 13:56:51 2025] usb 2-1.4.1: SerialNumber: xxx
[Wed Jan 22 13:56:51 2025] r8152-cfgselector 2-1.4.1: reset SuperSpeed USB device number xx using xhci_hcd
[Wed Jan 22 13:56:51 2025] r8152 2-1.4.1:1.0: load rtl8153b-2 v2 04/27/23 successfully
[Wed Jan 22 13:56:51 2025] r8152 2-1.4.1:1.0 eth0: v1.12.13
[Wed Jan 22 13:56:51 2025] r8152 2-1.4.1:1.0 xxx: renamed from eth0
[Wed Jan 22 13:56:51 2025] scsi 3:0:0:0: Direct-Access     Generic  MassStorageClass xx PQ: 0 ANSI: xx
[Wed Jan 22 13:56:51 2025] scsi 3:0:0:1: Direct-Access     Generic  MassStorageClass xx PQ: 0 ANSI: xx
[Wed Jan 22 13:56:51 2025] sd 3:0:0:0: Attached scsi generic sg1 type 0
[Wed Jan 22 13:56:51 2025] sd 3:0:0:1: Attached scsi generic sg2 type 0
[Wed Jan 22 13:56:51 2025] sd 3:0:0:0: [sdb] Media removed, stopped polling
[Wed Jan 22 13:56:51 2025] sd 3:0:0:0: [sdb] Attached SCSI removable disk
[Wed Jan 22 13:56:52 2025] sd 3:0:0:1: [sdc] Media removed, stopped polling
[Wed Jan 22 13:56:52 2025] sd 3:0:0:1: [sdc] Attached SCSI removable disk

I am tending to believe that the issue is more about how the laptop is handling the power for the second screen. When I connect any other USB device, it tends to turn off the second screen and it does not turn it again. Neither after diconnecting and connecting the full adaptor. I need to turn off the computer and restart again several times until it catches the second screen properly.

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