[SOLVED] Second display without image

SolaireFanboy · 2026-09-11 11:29:55

Recently, I did a fresh reinstall on my desktop, using the KDE profile in the 'archinstall' script.
Now, whenever I attempt connecting a second display, namely a 4K TV, no output image shows up on it and the 'Display Configuration' settings screen from KDE Plasma flickers like this: 4 seconds showing both connected displays (1440p monitor connected with DisplayPort and TV) and their options -> menu window flicker -> another 4 seconds of both displays -> flicker -> ~1 second of automatic disconnection to TV display and greyed out options of only X11 scaling and screen tearing -> flicker -> automatic reconnection to TV and the loop restarts.
At first, the resolution on the monitor also changed to what I presume was 3840x2160p, since some of the screen went missing, but resetting the monitor's resolution and making the TV mirror the contents of the monitor seemed to fix that problem.

I had no issues with my previous installation and have no issues connecting my laptop, also installed with Arch and KDE, with the same HDMI cable to the TV.
Desktop GPU: AMD RX 6700XT with latest mesa and Vulkan drivers, including 32-bit variants
Laptop GPU: NVidia MX350 with latest Intel and NVidia drivers

Things I've tried:
- connecting the desktop to the monitor with the "faulty" HDMI cable: works fine
- connecting the laptop to the TV with the "faulty" HDMI cable: works fine
- connecting the desktop to the monitor with another HDMI cable: works fine
- setting the refresh rate to the same value for both the monitor and TV: still no output
- changing the resolution on both displays: still no output
- updating both computers to the latest versions of all installed packages: still no output
- comparing explicitly installed packages (pacman -Qe) between computers: seemingly not much different besides a smaller list of Xorg packages on the desktop, but 'xorg-xrandr', 'xorg-server-common' and 'xorg-xwayland' are installed

EDIT:

Migrated the post from "Applications & Desktop Environments" to "Kernel & Hardware" after seeing similar posts:
- Monitor not working anymore after an upgrade.
- [AMDGPU] 4:2:0 output via HDMI seems broken since kernel 7.2

EDIT FOR [SOLVED]:

Installing and booting from the LTS kernel solves the issue.

Last edited by SolaireFanboy (Yesterday 20:42:54)

seth · 2026-09-12 17:26:37

Have you confirmed that you're hitting the same regression(eg. by testing the LTS kernel)?

SolaireFanboy · 2026-09-13 01:34:52

seth wrote:

Have you confirmed that you're hitting the same regression(eg. by testing the LTS kernel)?

I'd attempt checking out the LTS kernel, but Grub ain't listing the installed kernels even after following the wiki's instructions: updating the "grub" file and reloading the config file with "grub-mkconfig". Any tips on fixing that?

seth · 2026-09-13 06:21:04

ls -lR /boot
cat /boot/grub/grub.cfg

nb. that what currently breaks stuff for amdgpu is actually the firmware, downgrading linux-firmware-amdgpu to see whether it's coming from there might be worth a shot.

SolaireFanboy · Yesterday 10:45:58

seth wrote:

nb. that what currently breaks stuff for amdgpu is actually the firmware, downgrading linux-firmware-amdgpu to see whether it's coming from there might be worth a shot.

On the current 7.2.4 kernel, I've just tried out multiple versions of "linux-firmware-amdgpu", namely a couple of the last 2 months, the version from April 10th 2026 and even the version from June 27th 2025: all of them showed the exact same behavior as the current version after installation, reboot and plugging in the HDMI cable to the TV.

Last edited by SolaireFanboy (Yesterday 10:47:27)

seth · Yesterday 14:30:13

Did you figure how to install linux-lts?
If not, please post the outputs of the commands in #4

SolaireFanboy · Yesterday 15:19:30

seth wrote:

Did you figure how to install linux-lts?
If not, please post the outputs of the commands in #4

I did install it, but I can't select it in GRUB, the only options there are "Arch Linux" (current kernel) and "UEFI Firmware Settings".

Output for /boot directory listing: https://pastebin.com/kZCVNirG
grub config (after checking that linux-lts is installed and after running grub-mkconfig): https://pastebin.com/z3xZEStp

seth · Yesterday 15:58:10

You installed it as regular initramfs/kernel but grub is configured to only load UKIs (probably because you used the archinstall script)
=> https://wiki.archlinux.org/title/Unified_kernel_image

Docbroke · Yesterday 16:44:07

I think op need to run grub-mkconfig command, something like below, depending on how you installed arch

grub-mkconfig -o /boot/grub/grub.cfg

EDIT: missed that op has already tried this.

Last edited by Docbroke (Yesterday 16:45:51)

SolaireFanboy · Yesterday 20:39:12

It worked! Both installing the LTS kernel and making the TV work as a display!

By generating the LTS UKI with kernel-install, the LTS kernel appeared as an option in GRUB (granted, with the name as Arch Linux, the same as the current kernel, so that's a bit confusing) and the PC boots no problem. I did attempt chainloading the UKI, but it just adds another entry below "UEFI settings" and I may have screwed up the UUID (it's the /boot partition's right? XXXX-XXXX) because the PC couldn't boot with that option, stating that it failed to mount /boot.

Anyhow, really appreciate the help, I hope the current kernel can resolve this display issue soon.

Last edited by SolaireFanboy (Yesterday 20:39:55)

seth · Yesterday 21:40:35

with the name as Arch Linux, the same as the current kernel, so that's a bit confusing

https://bbs.archlinux.org/viewtopic.php?id=314538
Forego the uki script from archinstall and use https://wiki.archlinux.org/title/GRUB#C … rnel_image

Arch Linux

#1 2026-09-11 11:29:55