Resolution issues with two monitors

nomorewindows · 2025-04-06 16:02:25

seth wrote:

You're clearly not using the xe module on either kernel, where does that idea come from? Some difference in the xorg log?
5.10.16-rt30-1-rt - 5.10.16 is notably a realtime kernel and
Mar 30 15:27:16 archlinux kernel:  drm_dp_cec_set_edid+0x163/0x1d9 [drm_kms_helper]
Mar 30 15:27:16 archlinux kernel:  intel_dp_set_edid+0x238/0x2a0 [i915]
Mar 30 15:27:16 archlinux kernel:  intel_dp_detect+0x1bc/0x680 [i915]
apparently fails to expose the DP EDID to the drm subsystem?
for OUT in /sys/class/drm/card*; do echo $OUT; edid-decode $OUT/edid; echo "================="; done
You'll need https://github.com/timvideos/edid-decode/ (not yet in v4l-utils and the AUR package is unfortunately gone)
Do you use "drm.edid_firmware=…" on either of those boots?
Next:
Mar 21 13:18:31 archlinux kernel: kvm: unknown parameter 'enable_virt_at_load' ignored
??

There's read-edid in extra. Didn't help a whole lot. Said that it is an SandyBridge/IvyBridge, and the edid was not hex.

And then libdisplay-info is installed already. It has a di-edid-decode function, and under the current kernel, shows the proper resolutions. So if it doesn't show them again under the kernel 6, then something's up.

Last edited by nomorewindows (2025-04-06 18:16:32)

seth · 2025-04-06 21:34:44

read-edid isn't that great, but you can copy the edid resp. cat it into 0x0.st.
The main information however is whether they differ between 5.10 and 6.x

nomorewindows · 2025-04-07 14:11:29

seth wrote:

read-edid isn't that great, but you can copy the edid resp. cat it into 0x0.st.
The main information however is whether they differ between 5.10 and 6.x

So for some reason now it reads 4k on both 5 and 6. But there's something strange going on at boot time. For whatever reason, I can have all the displays plugged in, but no video and it doesn't boot. But with VGA only, it boots, and then after the login screen comes up, then I can plug the DP 4k screen back in, and do startx. It'll do both screens at VGA resolution, and then the option for 4k shows up in xrandr. Have to engage 4k manually with xrandr/arandr.

I have no idea.

Kernel 5 seemed to call it card0, while kernel 6 calls it card1.

Last edited by nomorewindows (2025-04-07 14:12:58)

seth · 2025-04-08 18:47:45

I have no idea.

But journals and Xorg logs - and we don't.

nomorewindows · 2025-05-27 01:06:13

Don't know if it makes any difference, but UEFI implementations maybe hiding messages such as you need to change your battery because the screen is blank until boot loader boots up is another folly of that. Changed CMOS battery.

But this video is rated I for insane.

https://youtu.be/eaS7Bd9a9RM

Removed the power supply and the whole processor fan assembly to get to a buried watch battery. Not necessary. Just remove the fan clips, and slide fan up and pluck the battery out and replace. Put fan back down and clip.

Still requires me to unplug displayport adapter to hdmi and boot with VGA, but at least it boots a little more reliably.

Last edited by nomorewindows (2025-05-27 01:07:48)

seth · 2025-05-27 07:01:49

Did you check the journal and/or xorg log or do you want to post them for peer review?

Arch Linux

#26 2025-04-06 16:02:25

Re: Resolution issues with two monitors

#27 2025-04-06 21:34:44

Re: Resolution issues with two monitors

#28 2025-04-07 14:11:29

Re: Resolution issues with two monitors

#29 2025-04-08 18:47:45

Re: Resolution issues with two monitors

#30 2025-05-27 01:06:13

Re: Resolution issues with two monitors

#31 2025-05-27 07:01:49

Re: Resolution issues with two monitors

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