KVM switch + Windows 7 creates monitor switching nightmare

I would definetly like to try this app you created.  I also believe this was caused by a MS patch since it was working well and then one day I noticed this became a problem.

I too am having the KVM switching issue. My setup is:

• Dell Optiplex 960 with an ATI(AMD) HD 3450 running Windows 7 32bit
• Dell Latitiude E6400 running Windows XP
• Starview SV231DD2DUA dual DVI KVM

The problem is, of course, when switching from the XP machine back to Windows 7 all open windows are resized and moved back to the upper left corner of monitor 1. The KVM mfg. support insists that it is a problem with Win 7, however, I have to believe that the KVM also is involved becuase a co-worker with the same setup but a different KVM (IOGear) does not have this problem.

I have researched this quite a bit and have experimented with the EDID-OVERRIDE feature in Windows on the monitor driver but it did not help correct the problem at all.

This is obviously an issue with Win 7 that a number of people are having but M$ does not seem to want to address it. It is monumentally frustrating!!!

I have found a work-around.

Using Sysinternals ProcessMonitor I found that Windows was accessing the following Registry path;

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\GraphicsDrivers\Configuration

My system had three entries;

DELF003YY7707BR0MUL_30_07D7_6A^9A3774EB79DEE3E3E38496CC7DF4D936

QHD32000001_31_07D6_D5^63E1ABDD175E7871DCAEB710418A0F75

SIMULATED_8086_2A42_00000000_00020000_1010100^CDE365D1B3F0942F0CF38BFB8E127AB4

Under each is a tree called "00" two of the keys are

PrimSurfSize.cx

PrimSurfSize.cy

Under "00" was another branch also called "00" two of the keys are;

ActiveSize.cx

ActiveSize.cy

The first two of the configs (ie DELF00... & QHD3...) the above keys were 1440x900,

so they were not involved.

The third (SIMULATED...) were set to 1024x768.

I changed these to 1600x900 and the problem was solved.

Further I changed resolution (via control panel) to 1920x1080, the moving/resize issue returned,

but the lower right corner was set to 1600x900, ie the SIMULATED... settings.

So for some reason one of the configs does not get set correctly.

I don't know why there are three configs, I have only ever used one monitor.

Worked for my non KVM switch issue, may help your issues.

I found this a While back, before finding this thread, or I would have posted the same.  This helped for the changing of the resolution issue, but I still have an the issue of my system being set back to single monitor.  The setup I had was working for a long time without issues, then one day this started for me, within the last month, so I thought it was a patch that was applied that caused this issue.  After not getting any answers on how to fix this, I started digging to see how I could at least, quickly restore my monitors' setup.  I found that going into the screen resolution and clicking detect, set the monitors back to  the original setup, so I wanted to try to duplicate it.  

I wrote a small app, probably could even do this with a script of some sort, that extends my desktop back across my secondary monitor. I basically have my app, check if the monitor is set to extend my desktop and if not, run DisplaySwitch.exe in system32 with the /extend to extend the desktop to that monitor.  I did this in C# because I try to use all of these little things as learning experiences to do other things later. Anyways.

I'm working on making this a service that runs all the time and checks to see if it changes and then fix my monitors if one gets deactivated.  While this isn't a fix, thanks MS, it is a band-aid to my problem. 

If anyone wants to try this, let me know.

I've researched this quite a bit.  I first saw it with Windows 7 but I've since seen it on other operating systems including Linux and Windows XP.  It's not so much an operating system issue as a driver issue.  I have an 8-port KVM which is where my problems started.  I was fine until 6-8 months ago when I started upgrading hardware and software.  The bottom line is that it was really the video card upgrades that were at fault for me, with some blame placed on the operating systems and drivers for their inconsistency in being able to compensate.

One solution, which I'm using for one machine, is to use a DDC/EDID emulator like one of these:  http://www.connectpro.com/prod\_vid\_ddc.html

That's much cheaper than getting a new KVM but, unfortunately, you need one for every connection where the issue exists (not just one for the KVM).

On Linux, with an NVIDIA card, their drivers handle it.  If I run with the stock Linux drivers I can't use high resolutions without screen flashing, etc.  With NVIDIA's drivers, it's handled. I believe that may be a function of X Windows though -- there are ways to configure DDC/EDID settings for the display that compensate for the KVM not doing it.

With NVIDIA on XP, no such luck.  I use NVIDIA's drivers but I have to use the DDC/EDID emulator to get high resolutions like 1920x1200 without the flicker problems.

On Windows 7, with a Radeon card, same thing: without adding the DDC/EDID emulator I have to run at lower resolutions to avoid issues.

In all cases I'm okay with any of the 1600/1680 resolutions and below.

As for replacing your KVM, you need to buy a DVI KVM to get around this without attaching an emulator device.  I did some experiments and my goal now is to eventually move to a full DVI KVM.  I believe only VGA KVM's suffer from this issue (since they were created before the protocol really).  When I use DVI versus VGA I get a much better display.  So ultimately I want to replace my VGA KVM with a DVI KVM that supports DDC/EDID.  That will fix the problem for any machine I plug in and get me better quality displays.  If you read the manufacturer specs you'll see that most or all DVI KVM's discuss supporting this.  There are two issues I've found with DVI KVM's: price and capacity.  Price is a big barrier to me replacing my VGA KVM now but at some point I'll justify spending the money.  Capacity is a bigger issue.  I have an 8-port VGA KVM.  I'm not using all 8 ports but plan on getting there in a year or so (this is a small business KVM).  One reason I got the KVM I have is because I can cascade others to it to go beyond 8 ports if I ever get that far.  There aren't many DVI KVM's with more than 4 ports -- some but not a lot.  On top of that, only a few I found are cascadable.  If you only need 4 ports, then you can get a reasonably priced Belkin or IOGear DVI KVM.  To go higher or get cascadability, you need to start looking at Avocent, Gefen, Adder, or SmartAVI (there are probably more).  Some of those are very nice products but they're all also rather pricey right now.  You will easily spend close to $1000 or more for an 8 port DVI KVM.

It would seem if drivers like NVIDA can compensate on Linux there would be some way to do the same on other systems and with other graphics cards.  That's really what I want now: a workaround to let me use 1920x1200 without buying anything to hold me over until I'm ready to upgrade my KVM.   I find the "upgrade your hardware" answer annoying given the cost difference.  It's not a trivial upgrade for most people who don't have an extra $1000 or so laying around to spend.

I have found a work-around.

Using Sysinternals ProcessMonitor I found that Windows was accessing the following Registry path;

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\GraphicsDrivers\Configuration

My system had three entries;

DELF003YY7707BR0MUL_30_07D7_6A^9A3774EB79DEE3E3E38496CC7DF4D936

QHD32000001_31_07D6_D5^63E1ABDD175E7871DCAEB710418A0F75

SIMULATED_8086_2A42_00000000_00020000_1010100^CDE365D1B3F0942F0CF38BFB8E127AB4

Under each is a tree called "00" two of the keys are

PrimSurfSize.cx

PrimSurfSize.cy

Under "00" was another branch also called "00" two of the keys are;

ActiveSize.cx

ActiveSize.cy

The first two of the configs (ie DELF00... & QHD3...) the above keys were 1440x900,

so they were not involved.

The third (SIMULATED...) were set to 1024x768.

I changed these to 1600x900 and the problem was solved.

Further I changed resolution (via control panel) to 1920x1080, the moving/resize issue returned,

but the lower right corner was set to 1600x900, ie the SIMULATED... settings.

So for some reason one of the configs does not get set correctly.

I don't know why there are three configs, I have only ever used one monitor.

Worked for my non KVM switch issue, may help your issues.