Perceived, but not actual, resolution change when adding monitor

[Weatherlite]

I apologize in advance...this is probably going to be a weird on. Also, some might suggest I go to the manufacturer of my 3rd party hardware. I have, and they are stumped, but also feel that it's an issue with the computer based off the symptoms I will soon explain.


I run a dispatch center, and at each station we have four computers running a total of seven screens. Computer A has one screen, B has four, C has one, D has one. Last year we added a BlackBox Freedom II KVM which allows us to operate on all seven screens with a single mouse and keyboard seamlessly...basically it acts just like a single computer. As the mouse travels along the screen, the KVM "counts" the number of pixels so it knows when it hits the edge of the screen and must change from computer A to computer B. It does require telling the KVM what our setup physically looks like, as well as the monitor resolution, so it can track properly. I have played around and added monitors, removed them, duplicated a couple, and it all worked flawlessly. Until now. Previously, I would add a monitor in landscape mode and would get zero problems. In fact, I just added a 50" TV to station 3 as a room display map and had no issues. However, I tried adding in a different 50" TV to station 2, but in portrait mode, and everything goes to hell.


Our monitors are set up with four across the bottom, and three across the top set to far right. For our purposes here, ignore the bottom four screens. The top three, from left to right, are computer B, C, and D. All are identical monitors and all are set to 1920 x 1080 in landscape. If I add a second monitor to C, set to landscape, and set to 1920 x 1080, and align both windows and the KVM to show the monitor as being beside the original monitor, things work fine. Move the mouse from the lower left of monitor D1 over to monitor C2 and it appears in the lower right, as it should. Movement between all of the monitors happens properly. However, if I change monitor C2 to portrait, or even if I keep it in landscape but change its location vertically at all (in Windows and in KVM....both must match) suddenly the system somehow changes the perceived resolution of monitor C1.


A little difficult to follow, so I'll try to clarify. Basic setup is BCD. If I add a monitor to C it becomes B C1 C2 D and works fine. If I keep that monitor attached but change configuration so it's now B C1 D, and C2 is anywhere other than directly beside C1, it's like the computer thinks C1 now has a resolution of 1920 x 540. As an explanation, when I move from the lower left corner of D onto C1, it appears in the lower right corner of C1, as it should. But, if I move up 2 inches on D and move to the left, the mouse appears 4 inches up on C1. At the halfway point up D the mouse appears in the very top right of C1. Even mouse speed is affected when moving vertically. I know the 1920 part of the resolution is unaffected because mouse speed is the same and mouse movement up and down between monitors is fine as well.


What I see on the screen, how icons are arranged, etc remains unchanged. The computer even says it's still at 1920 x 1080. It's sure not acting like it, though. If I turn off monitor C2, everything returns to normal and transitions between B/D and C is just fine. Ideas? And I included a couple configuration pics to help make sense of what I tried to describe. Thanks in advance!

 

[iko22]

Hello Weatherlite and Welcome to the Forum,

What happens if you switch monitors B2, B3 or B4 into Portrait mode? Does the resolution of B1 appear to change?
And, what happens should you swap monitor C1 with monitor C2? Then put monitor C1 into portrait mode? Is the problem solved this way, or do you get similar symptoms now on C2?

What I am trying to do is generate more examples of the issue, in order to determine which component or peripheral is at fault.

 

[Weatherlite]

I don't know why I didn't think of trying that before. Kinda feel silly for not having the information prior. lol So, I tried changing locations, format (portrait vs landscape), and swapped C1 with C2. When I changed monitors on B, everything worked as one should expect, regardless of which monitor I made the changes on. When I swapped monitors between C1 and C2 (I swapped them positionally and also tried swapping ports on the computer) and I got the same results as before...the mouse arrives at the wrong spots.


I did, however, realize that the computer is basically treating the two monitors as a single monitor with the vertical resolution being split between the two. Using the last diagram I provided, when I move slightly above the halfway point on D to C, it appeared on the very low/right corner of C2. When I moved from the top right of C2 to the right, it appeared at the top left of D. So it's definitely splitting the 1080 portion and leaving 1920 alone. When I swap C2 to portrait and position C2 above C1, moving from the top half of D arrived on the bottom of C2 for maybe 1/4 of the screen, so it's almost like it's cramming the 1920 of vertical (it's in portrait) above the 540.



So odd!


Oh, this may have some bearing.....C1 is plugged into a DP converted into DVI and C2 is HDMI.

 

[iko22]

Can you re-boot the computer attached to monitor C2, after this C2 monitor has been set to portrait? Does re-booting the computer resolve the issue?

 

[Weatherlite]

Unfortunately that doesn't work either. I'm still waiting on a DP hub to try that idea out. Never had a problem mixing port types before, but ya never know.