Display not working (black screen) since kernel 7.1.6

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1

I have a machine with four AMD R9700 GPUs installed. Display is a 4K TV connected via HDMI to an ASUS Turbo R9700 card - the other three R9700’s are ASRock Creators.

Was working fine through the 7.1.5 kernel, and hasn’t worked with any kernels since, up to 7.1.10. Booting with the old kernel and waiting for an update doesn’t seem to be the right approach at this point.

I notice in the boot log that under 7.1.5 the HDMI port is correctly identified (or at least labeled) as HDMI-A-1 (I think) while the 7.1.10 boot log labels it DP-16 instead. Not sure if that’s related or not.

using modprobe.blacklist=amdgpu allows the display to work but at a very low resolution.

I can ssh into the machine from another computer once I blindly type in the LUKS password.

Using AI has been tangentially educational but hasn’t solved the problem.

The TV is a Vizio M55Q6-L4.

Any ideas / recommendations?

2

I think you can add something like video=DP-1:d to your kernel command line to disable the display port.[1]

  1. I’m assuming DP-16 is a typo and you don’t actually have 16 display port connections. If you do have more display port connections that you need to disable, I think you can specify that video= parameter multiple times. ↩︎

4

DP-16 is the correct name, there are four GPUs with four ports each and it numbers them sequentially across cards. All the ports are DP except for one on the ASUS, which has three DP and one HDMI.

Under 7.1.5 the ports are labeled DP-1 through DP-15, and HDMI-A-1 for the single HDMI port.

Under 7.1.10, the ports are labeled DP-1 through DP-16 - apparently the HDMI is incorrectly detected as DP.

5

It sounds like an edge case that is not being handled correctly in the driver. You might have better luck reporting the problem on the AMD issue tracker here: https://gitlab.freedesktop.org/drm/amd/-/work_items?sort=created_date&state=opened&first_page_size=100