DisplayPort will not show anything on cold boot

[VitrasSlade]

I recently built a second desktop so I have one Windows gaming rig and a primary Linux desktop, both equipped with Intel i cores and MSI Nvidia GTX dedicated graphics cards. The Linux machine is running off of a MSI Skylake board and the Windows rig has a MSI Haswell board. I bought a DisplayPort KVM switch so I could keep one set of peripherals. I have them hooked up to a LG 29" ultrawide monitor.

When I cold boot either computer it will not display the BIOS or splash screen. Linux will not show login screen after splash screen, but Windows will. If I reset (or shutdown and boot again) it will display correctly. I have had this problem before getting the switch, so I know that factor is not an issue.

Halp please.

 

[bjornl]

Video card initialization should be the same on a hot or cold boot.

I would test one at a time with the monitor without the KVM.

I would test one at a time with a different monitor without the KVM.

I would then test one at a time with various cables through the KVM.

I would then test one at a time with various cables through the KVM but with the different monitor.

The computers don't seem to have a lot in common with each other beyond brand names of the parts. And MSI is fine in this regards.

So that means the likely points of failure are the KVM or the monitor.

 

[VitrasSlade]

As I had said before, the problem is not switch. It has happened before without a switch and the PC had a different configuration. I was thinking the monitor may be the problem also. I wanted to check here in case it was a BIOS option or a known DP issue so I could save a trip from pulling another monitor out of storage.

 

[bjornl]

There is no BIOS option to change the DP such that it only initializes the monitor on a hot-restart. That would be controlled by the driver, and those don't use the same driver. Also I haven't seen a driver setting that could cause this.

 

[techgeek]

A quick question, you have a single monitor / keyboard / mouse shared between these two computers. Do either of these computers have a second monitor connected directly to them? It may not be relevant, it's just tweaking something in my head is all.

 

[VitrasSlade]

Nope, no second monitor. Just the single monitor connected through the KVM switch.

 

[techgeek]

Without the switch and either computer plugged directly into the monitor, do you consistently get a POST screen and everything works normally on a cold boot?

 

[VitrasSlade]

I double checked just to be sure, DisplayPort does not work on cold boot even if connected directly to either PC. Linux will not display anything even upon reaching login screen, but Windows will start displaying at login. I found that for Linux unplugging and plugging DP cable made it display (as well as restarting, like before).

I tried an HDMI to DP cable, with DP in the Windows system and HDMI in the monitor (no switch). Everything displayed correctly. If I reversed the cable, nothing displays at all, even after unplugging and plugging, or restart. That may have to do with HDMI and DP compatibility, so I am not sure if it's significant... After waiting for a cold boot, I will try using the cable to plug into HDMI port of monitor and DP port in switch and see if it'll work for now... I am looking at getting a new monitor anyway, so it might do for now if it is the monitor's DP port at fault.

Sadly, I discovered my monitor in storage has no DP port. I have the only monitor in the house with DP port. Derp.