Everything worked fine on 4.18 and 4.19 was ok but fickle. As of 4.20, GNOME shell won't recognize the external display at all. I plug it in and the main laptop screen goes black and the monitor continues to be in power-save mode. If I unplug, everything goes back to normal on my laptop. Maybe the link just never trains?
I've tried with two different Dell monitors with two different USB-C HDMI adapters (Cabel Matters and a Kensington dock) and with and without my KVM switch. None of it makes a difference.
Hardware: Dell XPS 13 9360 (KBL-R)
Kernel: 4.19.13 is okish, 4.20.15 and 5.0.4 are broken. All kernels are Fedora builds
Userspace: Fedora 29 with GNOME Wayland, everything updated
Can you please try to reproduce the issue using drm-tip (https://cgit.freedesktop.org/drm-tip) and kernel parameters drm.debug=0x1e log_buf_len=4M, and if the problem persists attach the full dmesg from boot.
Jason, any updates from drmtip?
It doesn't work with drm-tip but I also haven't sat down and gotten logs. The one update I do have is that I bought a new dock and it works fine. I think it has something to do with the fact that my old dock supported both HDMI and displayport and did internal MST.
(In reply to Jason Ekstrand from comment #3)
> It doesn't work with drm-tip but I also haven't sat down and gotten logs.
> The one update I do have is that I bought a new dock and it works fine. I
> think it has something to do with the fact that my old dock supported both
> HDMI and displayport and did internal MST.
We need dmesg log from drmtip to investigate the issue. Can you please re-test with latest drmtip and attach the logs? This will speed up the investigation.
Need latest logs from drm-tip to investigate the issue.
No feedback for more than a month, closing as resolved works for me.
Please re-open if issue persists with latest drm-tip https://cgit.freedesktop.org/drm-tip and send dmesg from boot with kernel parameters drm.debug=0x1e log_buf_len=4M?