DisplayPort Alt Mode (DP-1) not detected after kernel update

Support Graphics & Display
1

Hi all, I’m new in the forum. (Sorry if this is not the proper way to notify an issue)

Today I had this problem:

SYMPTOMS:

  • Secondary monitor (BenQ) connected via USB-C hub was no longer detected
  • xrandr only showed HDMI-A-1, DP-1 status was “disconnected”
  • System worked fine days before with the same hardware
  • USB devices (keyboard, mouse) on the hub worked normally
  • Issue appeared after recent kernel/system updates

ROOT CAUSE:

  • Kernel 6.18.12 broke DisplayPort Alt Mode detection on Intel Iris Xe (i915 driver)
  • DP-1 port remained disabled despite physical connection
  • Not a hardware failure (USB functions confirmed working)
  • Not a BIOS setting (verified later)

SOLUTION:
Downgrade kernel from 6.18.12 to 6.18.4:

  1. Install kernel from pacman cache:
    sudo pacman -U /var/cache/pacman/pkg/linux618-6.18.4-1-x86_64.pkg.tar.zst

  2. Reboot system

  3. Verify detection:
    xrandr

RESULT:
✓ DP-1 now detected and working
✓ Dual monitor setup (3840x1080 extended)
✓ Both monitors at 1920x1080@59.96Hz

2

Hi @rommond, and welcome!

Thank you for the information.

Installing/using an older version of the available software is generally discouraged and not supported as it puts y6our system in an unsupported, partially-updated state.

Rather try using a different kernel, as Is listed with mhwd:

mhwd-kermel --list

Install it with:

sudo mhwd-kernel --install <kernelVersion>

Where <kernelVersion> is the version of the kernel you want to install, provided by the previous command.

1 Like
3

Hi @Mirdarthos !

Thanks for the quick response.

I switched to the latest LTS kernel in Manjaro. First I checked available kernels with mhwd-kernel --list, then installed LTS with sudo mhwd-kernel --install linux61.

Is this the proper way?

3 Likes
Hybrid graphics laptop (NVIDIA + Intel) - dual monitor setup (internal + HDMI) - second monitor not detected
4

It is, indeed. Well done!

5

Hi,
You know that you can install more than one kernel, i presume?
(possible: install 10, use one) :innocent:

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6

I know that monitors over USB is a thing, I never really got it, but that’s just me.

What I do speculate is why you are using the i915 driver when xe is available - and likely better suited.

Are you mixing issues?

Or should it be understood as the USB-C is supposed to map a display port?

As the drivers is provided by the kernel one could speculate that it is a kernel regression.

The kernel version 6.18.12 suggests you are using stable branch.

 $ mbn info linux618 -q
Branch         : unstable
Name           : linux618
Version        : 6.18.16-1
Repository     : core
Build Date     : Wed 04 Mar 2026 19:51:17 
Packager       : Manjaro Build Server <build@manjaro.org>
Branch         : testing
Name           : linux618
Version        : 6.18.12-1
Repository     : core
Build Date     : Mon 16 Feb 2026 22:35:51 
Packager       : Manjaro Build Server <build@manjaro.org>
Branch         : stable
Name           : linux618
Version        : 6.18.12-1
Repository     : core
Build Date     : Mon 16 Feb 2026 22:35:51 
Packager       : Manjaro Build Server <build@manjaro.org>

Besides the option to switch to an older version from your cache - you also have the option of switching to unstable branch, as it will provide a later version than the one you are using.

Switch to unstable branch an run a full system update

sudo pacman-mirrors -aSunstable && sudo pacman -Syu
7

Hi @linux-aarhus ,

Maybe I’m mixing things here indeed.
I have 2 external monitors via HDMI. One directly connected to the laptop and the other connected via USB hub using USB-C into the laptop.

@GaVenga I didn’t know about having several kernels installed until now. I’m new using linux :stuck_out_tongue:

In principle I prefer to use LTS versions instead of unstable versions if possible.

Thanks for the help.

1 Like
8

That is unique to Manjaro, as far as I know. Oh, sure, if Manjaro can do it, others can as well, but I think it’d have to be done manually and isn’t a feature like with Manjaro. Or something like that, anyway.

9

HDMI and DisplayPort is two different technologies with two different connector layouts.

Showing a port as disconnected is normal - if said port is not in use or not recognized.

To use the Iris driver, add the xe to the file /etc/mkinitcpio.conf in the MODULES=() line, then rebuild the init.

mkinitcpio -P
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10

LTS Kernel supported now in Manjaro: 6.18 / 6.12 / 6.6 / 6.1
(manjaro-settings-manager)

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