Arch Linux

nomorewindows

Member

Registered: 2010-04-03

Posts: 3,434

Re: Resolution issues with two monitors

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)

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I may have to CONSOLE you about your usage of ridiculously easy graphical interfaces...
Look ma, no mouse.

seth

Member

Registered: 2012-09-03

Posts: 63,501

Re: Resolution issues with two monitors

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

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nomorewindows

Member

Registered: 2010-04-03

Posts: 3,434

Re: Resolution issues with two monitors

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)

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I may have to CONSOLE you about your usage of ridiculously easy graphical interfaces...
Look ma, no mouse.

seth

Member

Registered: 2012-09-03

Posts: 63,501

Re: Resolution issues with two monitors

I have no idea.

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

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