Dual boot issues

Dirk Diggler · 5 Jul 2022 at 09:39

I'm dual booting Win 11 & Ubuntu. The BIOS is set to boot to Windows first and then Ubuntu, so if I want to boot into Ubuntu then I need to F11 into boot options, which to be honest is fine.

The issue is that when my monitor is connected via Display Port cable then I don't get any video output until the Windows login screen is showing, basically after BIOS splash screen. If I'm connected via HDMI then there is no issue. I need Display Port in order to get Gsync on my GTX1080.

I've tried to find a solution to the Display Port issue but having no success. I'm now wondering if there's a way I can reboot from Windows and straight into Linux without going via BIOS? I'm sure I was able to do this on a previous build years ago but I might have had a different setup.

This is a new Ubuntu installation so if I have to reinstall and do it differently then that's cool.

Buffalo2102 · 6 Jul 2022 at 08:39

I find it easier to boot to linux first and then select either linux or Windows from the grub bootloader menu. Works perfectly for me and doesn't need to go back to BIOS.

You could try a boot manager like easybcd or refind.

Hades · 6 Jul 2022 at 17:01

As above, Start with installing Windows (which it sounds like you have). Then install Linux on the same drive. Obviously mak a backup of any important files first. Allow Linux to partition the drive and install Linux alongside windows. Then the Linux bootloader will allow you to choose either Windows or Linux at boot time.

Linux plays nicer with Windows, than Windows does with Linux. This is why I say install Linux second so that it doesn't overwrite Windows.

Dirk Diggler · 6 Jul 2022 at 17:09

Hades said:
As above, Start with installing Windows (which it sounds like you have). Then install Linux on the same drive. Obviously mak a backup of any important files first. Allow Linux to partition the drive and install Linux alongside windows. Then the Linux bootloader will allow you to choose either Windows or Linux at boot time.

Linux plays nicer with Windows, than Windows does with Linux. This is why I say install Linux second so that it doesn't overwrite Windows.

It's set up exactly like that, but the issue is with the monitor because it won't accept video output via Display Port until Windows has loaded, therefore I never get to see the grub loader.

Hades · 6 Jul 2022 at 17:34

Hmmm that is odd. Not seen that before. Do you even see the BIOS screen via displayport (unplug HDMI so DP is the only connection)? Is there anything in the BIOS to specify the primary display?

Dirk Diggler · 6 Jul 2022 at 17:51

Hades said:
Hmmm that is odd. Not seen that before. Do you even see the BIOS screen via displayport (unplug HDMI so DP is the only connection)? Is there anything in the BIOS to specify the primary display?

No, but I think you may have hit on something there - I could possibly have HDMI and DP both connected to the GPU...

Hades · 6 Jul 2022 at 20:02

Regardless of windows or Linux I am pretty sure any device will only show the primary display until it gets into an OS.

I would expect it should boot with display port if only that cable is attached. Or at a push you might need to change the primary display to be displayport in the BIOS.