Why am I losing one of two dual monitors when using switching device?

Question

I have two computers, one running Windows 7 and one running Ubuntu 11.10. They are both connected to an Aten Masterview CS-1742 switching device, so that I can use the same keyboard, monitors, mouse, and USB peripherals for both machines.

The one problem is that whenever I switch away from, and then back to Windows, only one monitor is active.

So, every time I come back to windows, I have to open up my Nvidia settings dialog, which looks like this:

I click on "My display is not shown", which brings up this dialog:

I click on "Rigorous display detection", then my second monitor is detected, and everything is fine:

Obviously this is not ideal.

How do I get Windows to maintain both monitors when I switch back and forth using the monitor switcher?

Answer 1

I added a picture of the back of the device to provide more clarity as to what this device is doing. Typically what will happen when trying to use the same monitor, mouse, and keyboard with another computer is that you will unplug the devices and plug them into the new computer. That being said, it's annoying and the KVM switch you have solves that annoyance. However, when you unplug the devices to plus into the other computer, the first computer sees that devices were unplugged and hence causing it to lose a monitor. When you plug the devices back in, it "re-adds the hardware". Most KVMs that I see will have a presence of the monitors, keyboards and mouse to where both computers have no idea that something was unplugged. If you remember back in the day, most computers' BIOS had it set by default to give an error where a keyboard was not present. The KVMs back then would keep alive the connection to fool the machine that you're not currently using to see the presence of a keyboard, monitor and mouse. It sounds like your KVM switch is not doing that.

Here is a link to the latest firmware for your device (2/2009)

http://www.aten-usa.com/export.php?mid=20090217132025002&type=firmwave

There's no guarantee that this would help, but could be a possible solution. The only other thing that I can think of is if you're using any adapters (DVI to VGA) or (HDMI to VGA) or (DisplayPort to VGA) on your monitors and/or connection to the KVM Switch. I don't know, but there could be a compatibility issue where when the switch to the other computer is made, it will not keep a persistent presence due to the adapter.