Any tips for debugging external video monitor not being detected in F38

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1

Hi,
Asking for any tips or advice on how to debug my external monitors not lighting up. Are there tools and logs for the kernel and wayland related to detection of monitors?
OS: Fedora 38 x86_64
Motherboard: ASUS Z790-P WiFI with i7-13700K, 32GB DDR5.
SBIOS: defaults to auto-detect of graphics
Re-sizable PCI BAR enabled.
Video Card: Intel ARC750 8GB
Monitors: 2 Dell 27" connected via DP compatible cables to ARC750 DP ports.

F38 installs on this system and everything works.
The default F38 enter suspend/resume works.
But on a recent resume, the second monitor was not turned on.
Since then I cannot get that monitor to be detected.
Power off system, remove power cord, turn off monitors.
Re-power everything and neither SBIOS or F38 will turn on the second monitor.
Now, F38 hangs during startup.
Tried clearing CMOS on the motherboard and setting SBIOS default settings. No luck.

  1. How does F38 no its resuming from standby. Is there a file written indicating this that I can modify/delete to make sure the OS is not trying to resume from a bad image written to swap?
  2. Since F38 uses zswap with BTRFS where is the resume image stored?
  3. What logs can I examine to find out what happened during a OS boot up/resume hard hang?
  4. Are the Dell monitors and ARC750 Display Port flaky or not compatible. Are there any linux tools to check Display Port connections?

Any info appreciated.

2

You should provide enough detail to allow others to reproduce the problem.
For hardware, paste the output of inxi -Fzxx as text (using the </> button).
I have seen similar issues when F38 was first released, but not recently. When reporting problems, it is best if you can fully update the system to avoid chasing issues that have aleady been fixed.

To rule out a problem with the monitor or cable, please try swapping the cables at the system connectors, and if that fails, swapping the cables at the monitor ends.

I’m not sure what you mean by “standby”. By default, “Suspend” is available. This just freezes memory contents and does not use a file. With extra steps you can enable “Hibernate”, which does use a file to preserve memory contents. Hibernate doesn’t provide much saving for systems using SSD’s, so is not widely used.

Log info is available from dmesg and journalctl. The latter is more complete, and will show more info if run with elevated privileges wth “sudo” or “doas”. You also edit the kernel command -line to remove “rhgb quiet” to see messages while the system is booting.

3

Does your monitor support HDR? Is it enabled? Try turning it off.