Arch Linux

bountykiller

Member

Registered: 2006-08-07

Posts: 23

Monitor not working anymore after an upgrade.

Hi,

I've got 2 monitor connected to my graphics card (amd radeon HD 7850).
It used to work, but after an upgrade, only one is working. The second stay black with a message telling that it receive no signals.
I've tried to use HDMI and display port ports, but neither is working.
In Xorg logs, I have the message "(EE) AMDGPU(0): drmmode_do_crtc_dpms cannot get last vblank counter" who does appears when I try to configure my screens.

I'm currenlty running kernel 7.2.2, but the bug was already present with previous ones.

What can I do in order to investigate further?

Last edited by bountykiller (2026-08-29 21:50:15)

bountykiller

Member

Registered: 2006-08-07

Posts: 23

Re: Monitor not working anymore after an upgrade.

Today I've switch to the linux-lts kernel, and my second monitor is working again.
So, I assume there is a regression somewhere between linux-6.18 and linux-7.1.

I'll try to refine this by using git bisect, like suggest here:
https://wiki.archlinux.org/title/Kernel … egressions.

I'll let you know if I found something interesting.

seth

Member

From: Won't reply 2 private help req

Registered: 2012-09-03

Posts: 77,682

Re: Monitor not working anymore after an upgrade.

Does "amdgpu.dc_feature_mask=0x0" help?
https://raw.githubusercontent.com/torva … meters.txt

They might have activated  FRL?

Last edited by seth (2026-08-30 15:37:34)

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bountykiller

Member

Registered: 2006-08-07

Posts: 23

Re: Monitor not working anymore after an upgrade.

Does "amdgpu.dc_feature_mask=0x0" help?
https://raw.githubusercontent.com/torva … meters.txt

They might have activated  FRL?

Just tried.

[    0.000000] Linux version 7.2.2-zen1-1-zen (linux-zen@archlinux) (gcc (GCC) 16.2.1 20260810, GNU ld (GNU Binutils) 2.47) #1 ZEN SMP PREEMPT_DYNAMIC Fri, 28 Aug 2026 16:40:27 +0000
[    0.000000] Command line: BOOT_IMAGE=/vmlinuz-linux-zen root=UUID=7fee6e25-b032-42ae-b7ef-de5be18cc28b rw quiet amdgpu.si_support=1 amdgpu.dc_feature_mask=0x0
...

I get a black screen :'(.

seth

Member

From: Won't reply 2 private help req

Registered: 2012-09-03

Posts: 77,682

Re: Monitor not working anymore after an upgrade.

amdgpu.si_support=1

Oh, that's a pitcairn (southern island) chip - do you run into the same issue w/ the radeon module (no, it's to check on what layer this occurs )

Edit: do you get kernel messages like in https://gitlab.freedesktop.org/drm/amd/ … items/5433 ?
Also https://gitlab.freedesktop.org/drm/amd/ … items/5258

Last edited by seth (2026-08-30 21:45:19)

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How to upload text · How to boot w/o GUI · Disable Windows Fast-Start! · Fix your xinitrc