Blank internal display once X starts

[cboettig]

Hi folks,

I've had my internal display go blank once the Gnome session starts. The display is fine during start-up / boot, but goes invisible once I reach the login screen. As long as I connect to an external display I can use the machine as normal, but just cannot see anything on the built-in display. Adjusting brightness hotkeys or xset dpms force off (from #50) doesn't fix anything.

I believe this happened after an upgrade about at 18.04 to 18.04.01, but attempting earlier versions (even 16.04 LTS) I see the same issue now.

I'm on XPS 13 (2015 linux dev edition), 9343. Have just updated to BIOS A18 but same issue persists.

Has anyone else encountered this issue? Any hints / suggestions on how to debug this?

[mpalourdio]

Hi,

never had such issues. Maybe you can try to mv ~/.Xauthority && ~/..ICEauthority and reboot to see if it fixes the problem

[mpalourdio]

You could try to boot on an ubuntu usb stick to eliminate the HW problem too !

[cboettig]

I see the the exact same behavior when booting on a USB stick too unfortunately.

[mpalourdio]

erf, looks like an HW issue :/

[mpalourdio]

What if you open another TTY once logged ?

[cboettig]

hmm, ctrl+alt+F8 shows only a black screen with the text:

drm:intel_dp_start_link_train [i915]] *ERROR* [CONNECTOR:59:eDP-1] Link training failed at rate 540000, lane count = 4

(this text shows up only on the external display, the built-in display remains blank)

[mpalourdio]

Looks very similar to this : https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1797881
Looks like a kernel downgrade can do the trick.

[cboettig]

yes it does indeed. Maybe I'm not reading the bug report properly, but seems like things should have worked then if I rolled back to 18.04, or back to 16.04? (Definitely used to work fine on 16.04).

What would you suggest I try? Upgrading the kernel to 4.19?

[mpalourdio]

Yes, definitely. I would try first a kernel upgrade.

Edit : I don't really see if the patch has landed in 4.19. You could try a kernel downgrade :

linux-image-4.18.0-7-generic has no problem
linux-image-4.18.0-10-generic has problem

So try to stick to 4.18.0-7

[cboettig]

hmm, I'm currently back on 16.04 with 4.15.0-29-generic and problem persists there...
what the heck, I'll try both. seems strange though this would impact some xps 13 9343s and not others(?)

[mpalourdio]

Try a cold boot. Shutdown completely, and reboot on 16.04. We've seen weird bugs not solved by soft boot when the 9343 has arrived, with i915 IIRC.

If that not works, I just really don't know :/

[mpalourdio]

Ensure too that you do not launch wayland, but Xorg. That may be the problem. AFAIK, wayland is not in 18.04 anymore. But maybe upgrading from 16.04 does not remove it. I use unbutu under the wood, because I am on linux mint/cinnamon from ages now. So I can be wrong

[cboettig]

@mpalourdio Updated to 4.19.7 kernel and my internal display is working again! Thanks very much for your help. (Also upgraded back to 18.04, though sticking with the advanced kernel version).