I'm on Ubuntu 19.04 as well and having issues with this. I have an i7-8750h paired with a gtx 1050ti in a Dell G515.
I don't exactly what I did, but I can give a general idea: I decided this morning that battery life was important to me, so I tinkered around with TLP. After I did that everything seemed fine, but when I plugged an HDMI cord back into my laptop, after reenabling my discrete GPU it no longer works. I have uninstalled and reinstalled TLP, I have reinstalled gdm3, no dice, and I have tried reverting just about everything I can think of that pertains to displays. I still can't get it. Switching over to lightdm for now, this is very frustrating though. Before I was working with TLP though, I was able to connect to external displays via this HDMI cord no problem. I know it is not a hardware issue because before I log in the external display shows the image I have for my lockscreen. However, it's once I log in that the display turns off. Hope this helps. I'd love to help get gdm3 working as well. LMK if you need anything including logs. -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to mutter in Ubuntu. https://bugs.launchpad.net/bugs/1716857 Title: gdm3, hybrid nvidia with modeset=1, no external monitors detected Status in gdm3 package in Ubuntu: Confirmed Status in mutter package in Ubuntu: Confirmed Status in gdm3 package in Debian: New Bug description: Context: 17.10 development packages, nvidia binary driver 375, modeset=1 for the nvidia driver. ubuntu desktop (gnome shell), fresh install ThinkPad W520 in Nvidia Optimus bios mode. Nvidia profile. Result: no external monitors are detected. xrandr does not even list them as disconnected (normally it would list five external disconnected monitors) lsmod shows that nvidia driver is loaded and the modesetting is working at some level because there is no tearing on the laptop panel Note: modeset=1 is the only way to get flicker-free graphics on the laptop panel. modeset=1 is not the default setting but it is highly desirable. It works if lightdm is used which is why I have reported this against gdm3 My sessions in this configuration have mostly crashed after a few minutes with a gdm3 fail whale message in syslog but nothing else looks interesting. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gdm3/+bug/1716857/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
