Arch Linux

bountykiller

Member

Registered: 2006-08-07

Posts: 24

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: 24

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: 77,741

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)

---

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

bountykiller

Member

Registered: 2006-08-07

Posts: 24

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: 77,741

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)

---

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

bountykiller

Member

Registered: 2006-08-07

Posts: 24

Re: Monitor not working anymore after an upgrade.

Yes, it's a pitcairn card

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

No I don't.
Instead, I have the following message which seems to be related to the issue:

...
[    4.271955] [drm] amdgpu: dpm initialized
[    4.273241] [drm] Found UVD firmware Version: 64.0 Family ID: 13
[    4.468079] amdgpu 0000:01:00.0: amdgpu: [drm] Display Core v3.2.359 initialized on DCE 6.0
[    4.671310] [drm:hwss_wait_for_blank_complete [amdgpu]] *ERROR* DC: failed to blank crtc!    <<< here

So far I haven't tested with the radeon module, as I'm trying to identify when the problem was introduced.
The latest kernel I've tested is version 6.19.12, and it has the issue.
The next i'll try will be 6.19.1. (As a reminder, linux-lts which is based on a 6.18 version doesn't have it).

CTth0ZZj

Member

Registered: Yesterday

Posts: 1

Re: Monitor not working anymore after an upgrade.

After upgrading from 7.1.* to 7.2 my monitor went blank. I had to delete the config file. I am fine at 1080p, but as soon as I go bigger…incidentally, an NVIDIA Shield Tv 2019 works using the same cable at 4K 60Hz, as did this before the latest update. It’s either the Kernel or the AMD driver. If anyone else has this try just swapping monitors. I wasted ages trying to troubleshoot this and more reversing everything I did.