HDMI output not working - Ubuntu 18.04, Metabox Prime 950EP

Graphics / Linux Linux
1

My HDMI monitor is detected in Displays but no output is appearing on the monitor. When i navigate to displays i can clearly see the external monitor is detected.

I’m running nvidia-driver-415:

➜  ~ ubuntu-drivers devices
== /sys/devices/pci0000:00/0000:00:01.0/0000:01:00.0 ==
modalias : pci:v000010DEd00001C20sv00001558sd000095E1bc03sc00i00
vendor   : NVIDIA Corporation
model    : GP106M [GeForce GTX 1060 Mobile]
driver   : nvidia-driver-396 - third-party free
driver   : nvidia-driver-410 - third-party free
driver   : nvidia-driver-415 - third-party free recommended
driver   : nvidia-driver-390 - third-party free
driver   : xserver-xorg-video-nouveau - distro free builtin

== /sys/devices/pci0000:00/0000:00:1f.3 ==
modalias : pci:v00008086d0000A348sv00001558sd000095E1bc04sc03i00
vendor   : Intel Corporation
driver   : oem-audio-hda-daily-dkms - third-party free

Output of dmesg:

➜  ~ dmesg | grep -i nvidia
[   13.073232] nvidia: module license 'NVIDIA' taints kernel.
[   13.085273] nvidia-nvlink: Nvlink Core is being initialized, major device number 240
[   13.085526] nvidia 0000:01:00.0: enabling device (0006 -> 0007)
[   13.085625] nvidia 0000:01:00.0: vgaarb: changed VGA decodes: olddecodes=io+mem,decodes=none:owns=none
[   13.184989] NVRM: loading NVIDIA UNIX x86_64 Kernel Module  415.25  Wed Dec 12 10:22:08 CST 2018 (using threaded interrupts)
[   13.194597] nvidia-modeset: Loading NVIDIA Kernel Mode Setting Driver for UNIX platforms  415.25  Wed Dec 12 10:02:42 CST 2018
[   13.197097] [drm] [nvidia-drm] [GPU ID 0x00000100] Loading driver
[   15.457134] [drm] Initialized nvidia-drm 0.0.0 20160202 for 0000:01:00.0 on minor 1
[   15.477130] nvidia-uvm: Loaded the UVM driver in 8 mode, major device number 237

Output of xrandr:

➜  ~ xrandr --verbose
Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 8192 x 8192
XWAYLAND0 connected 1920x1080+0+0 (0x22) normal (normal left inverted right x axis y axis) 340mm x 190mm
	Identifier: 0x21
	Timestamp:  24171
	Subpixel:   unknown
	Gamma:      1.0:1.0:1.0
	Brightness: 0.0
	Clones:    
	CRTC:       0
	CRTCs:      0
	Transform:  1.000000 0.000000 0.000000
	            0.000000 1.000000 0.000000
	            0.000000 0.000000 1.000000
	           filter: 
  1920x1080 (0x22) 173.000MHz -HSync +VSync *current +preferred
        h: width  1920 start 2048 end 2248 total 2576 skew    0 clock  67.16KHz
        v: height 1080 start 1083 end 1088 total 1120           clock  59.96Hz

I have tried modifying

sudo nano /lib/modprobe.d/nvidia-kms.conf

by setting

options nvidia-drm modeset=0

but this had no effect so i set it back to

options nvidia-drm modeset=1

Is there anything else i can try?

2

Looks like you’re using wayland, not Xorg. Modify /etc/gdm/custom.conf
[daemon]
WaylandEnable=false

3

changing modeset like that doesn’t do anything if you don’t rebuild your kernel image. (update-initramfs -u)

So you may have thought you disabled it when you didn’t.

gdm3, modeset and external monitors don’t work with prime sync. There is no known fix, just long standing bug reports.

Change your display manager to lightdm, and keep modeset. (sddm works too). You should get your external monitor back.

Also, consider upgrading to ubuntu 18.10. Optimus works well in 18.10.

4

@TimRichardson: Thank you for your reply. I found it most helpful. I wouldn’t have thought of looking at the display manager…