When I try to enable SLI by using nvidia-xconfig --sli=on and reboot the system, Ubuntu does not succeed with normal bootup and keeps coming back to login - thus going into infinite loop.
Going into recovery mode and entering shell as root lets me see that SLI = on change was made in /etc/X11/xorg.conf.
It seems Ubuntu 16.04 LTS also suffered from a similar issue. Nvidia created a ticket #1929896. But the issue never got resolved.
Please let me know if anyone has run into a similar problem.
Disabled iommu through BIOS and kept SLI to Auto. It seems to be using both GPUs now. Hopefully this can be added to the instructions for enabling SLI for linux.
EHCI and XHCI are set to enabled as is USB mass drive support.
The weird behavior is that I tried a usb stick and it works fine on the ports. But when I try my external harddrive - it starts to beep and does not recognize the drive.
I eliminated problems with the drive, I have a laptop with Ubuntu 18.04 on it and the external drive works just fine there - so its not an issue with the connector cable or the drive itself.
This external drive is my backup location to be used with Ubuntu’s backup utility. But these drives do not work on the ports. The only thing I can think of is that somehow the voltage to these ports is altered - I read online that enabling IOMMU enables the usb. But of course doing so interferes with nvidia sli.
I should also mention that I have updated /etc/gdm3/custom.conf with the following:
GDM configuration storage
See /usr/share/gdm/gdm.schemas for a list of available options.
[daemon]
Uncoment the line below to force the login screen to use Xorg
WaylandEnable=false
Enabling automatic login
AutomaticLoginEnable = true
AutomaticLogin = user1
Enabling timed login
TimedLoginEnable = true
TimedLogin = user1
TimedLoginDelay = 10
[security]
[xdmcp]
[chooser]
[debug]
Uncomment the line below to turn on debugging
More verbose logs
Additionally lets the X server dump core if it crashes
This seems to be a “special feature” of some Gigabyte mainboards, the iommu setting interfering with the usb controllers, depending on setting usb2 or usb3 not working. I guess the thumbdrive is usb2 and works while the harddrive is usb3 and doesn’t work.
I didn’t mean the settings to enable the x/ehci controllers but a e/xhci handoff feature, which handoffs usb controll from bios to os.