FS#63079 - Linux 5.1.x breaks external monitors on Intel graphics

Attached to Project: Arch Linux
Opened by Bennett Piater (ClawOfLight) - Wednesday, 03 July 2019, 07:22 GMT
Last edited by Antonio Rojas (arojas) - Monday, 08 July 2019, 07:56 GMT
Task Type Bug Report
Category Packages: Core
Status Closed
Assigned To No-one
Architecture All
Severity High
Priority Normal
Reported Version
Due in Version Undecided
Due Date Undecided
Percent Complete 100%
Votes 0
Private No

Details

Description:
When using Linux 5.1.x and Intel graphics, external monitors are not detected at all, either by xrandr or a wayland compositor (sway).

Downgrading to 5.0.3 or 4.19 (lts) solves the problem.

Additional info:
* hw: Thinkpad T450s
* package version(s)
linux >= 5.1.x
* arch-general thread: https://lists.archlinux.org/pipermail/arch-general/2019-July/046584.html

Steps to reproduce:
- install a recent kernel
- plug in an external monitor
- xrandr and sway cannot see it.
This task depends upon

Closed by  Antonio Rojas (arojas)
Monday, 08 July 2019, 07:56 GMT
Reason for closing:  Works for me
Comment by kkl2401 (kkl2401) - Wednesday, 03 July 2019, 10:51 GMT
I suspect additional information will be needed because I have the same model (T450s), I'm on kernel 5.1.15 and I definitely successfully used an external display about a week ago.
Comment by Bennett Piater (ClawOfLight) - Wednesday, 03 July 2019, 11:25 GMT
Interesting. Could you try again when you get a chance?
I'll see if I can get useful logs somehow.
Comment by kkl2401 (kkl2401) - Wednesday, 03 July 2019, 12:14 GMT
I'll try, although I can't promise when; I've been sent to a new client and I don't have an external display there. But I checked pacman logs and I know that last Thursday, when I was having a presentation (and using a projector), I was already on 5.1.15.
Comment by Bennett Piater (ClawOfLight) - Wednesday, 03 July 2019, 12:41 GMT
Did you reboot after installing it?
Comment by kkl2401 (kkl2401) - Wednesday, 03 July 2019, 12:48 GMT
Yes, I never install a new kernel if I can't immediately reboot. :-) And even if I didn't, the previous version based on my pacman.log was 5.1.9, so still 5.1.x.
Comment by Bennett Piater (ClawOfLight) - Wednesday, 03 July 2019, 17:41 GMT
So... I rebooted twice on monday and never got video to work until I booted into linux-lts, but when trying to get logs today, it worked.
So I'm at a loss now.

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