KVM switch + Windows 7 creates monitor switching nightmare

Hi Chris,

The resistance is zero on both dongles I tested, so I think there's just a piece of wire connecting the pins.

I think my configuration also explains why I didn't have a problem with multiple monitors combined with the KVM switch. Both my monitors were connected with DVI-VGA dongles, so because of the shorted hot plug pin W7 always thought the monitors were plugged. The EDID override didn't play any part in it, and only helped the other problem of EDID not passing through the KVM switch.

I wonder what the real solution this whole mess would be. Seems like we would have to be able to, for each monitor, specify which combination of hot plug pin, load detection and EDID polling is used for detecting the pluggedness, and how often the polling should occur, if ever.

I was actually testing similar things this weekend as Xenubite.  To reiterate, my problem is my desktop is never auto-resized, and I want it to be (so once I understand what is unique about my setup, that information should be useful to almost everyone else).

HDMI 1.2 specification states "An HDMI Sink shall not assert high voltage level on its Hot Plug Detect pin when the E-EDID is not available for reading... The Hot Plug Detect pin may be asserted only when the +5V Power line from the Source is detected".  It also states "Note that many Sink devices simply connect the HPD signal to the +5V Power signal through a 1000 ohm resistor" and "An HDMI Sink shall indicate any change to the contents of the E-EDID by driving a low voltage

level on the Hot Plug Detect pin for at least 100 msec" [1].

My computer only considers my projector disconnected when the “Hot Plug Detect” (HPD) line is disconnected.  Further, the projector can be in standby or disconnected from power but connected via HDMI cable and Windows 7 will still use it for my desktop.  I checked and it just uses a 1000 ohm resistor from +5V pin to HPD pin.  I am not yet sure whether the +5V pin actually ends up powering the EDID ROM.  Assuming it does not (and a software solution is not provided), one possible hardware work-around may be to make adapters that break the HPD line and connect a 1k ohm resistor from +5V to HPD on the source side to prevent the HPD pin from ever being driven low.  Installing one at each Windows 7 monitor prior to a KVM should stop the resizing.

Xenubite, I expect that is what your DVI -> VGA connector does.  Can you check resistance from pin 14 to pin 16 on your DVI adapter?

I would much rather see this problem resolved in the software.  It is absolutely possible, I just do not know if it will ever be done.

-Chris

[1] http://www.hdmi.org/download/HDMI\_Specification\_1.2.pdf

Unlike some here, I have no problem if I come across as a microshaft hater.  Use Linux.  It works.  Fornicate you microsoft!

Good advice! I can come up with some more: Take your bicycle and go for a ride. Take on your skates and go skating on one of the lake around you (at least this one currently works here in Sweden). Use your DVD player and watch a good movie. All these advices will work. And similar to your advice they totally misses the point.

The point is that I, and several other people in this forum, have things we need or want to do with our computers. And the tasks can't be performed unless we use at least two computers, where at least one has Windows7 installed, a KVM-switch we already own and one screen.

My setup is

• One older computer with Windows XP where I have my scanners connected, one slide scanner and one film scanners (no drivers on GNU/Linux). Simple graphic card with VGA connector.
• One newer computer with Windows 7, 64bit, and my main applications, Adobe Photoshop Elements and Pinnacle Studio video editing (choice of applications are not negotiable). NVIDIA GeForce 8800 graphics with two DVI connectors and VGA to DVI adapter.
• One 21" CRT, Gateway, with VGA connector
• One KVM switch for VGA.

The setup worked prior to upgrading the newer computer from Windows XP to Windows 7.

My problem is that whenever I switch computer with the switch Windows 7 forgets on what connector on the graphic card the KVM is connected and the picture disappears and doesn't come back again.

The requirement for an useful solution is that it will enable me (and all other posters with similar equipment) to use our current equipment with Windows 7. Any solution that contains, switch KVM, switch operating system, or similar is not useful.

The reason I believe I can push this requirement quite hard is that the root of the problem is a stupid design decision that added a feature (continually checking the monitor) that doesn't give any benefit to the user.

And by the way, diemsdie, I'm not a GNU/Linux hater. I'm using it for software development at work, but I believe in the right tool for the job.

Already using Linux. That's not the problem here. Your answer was not helpful. But Microsofts answer wasn't helpful either.

Btw, why don't I get a cursor while typing here? Extremely annoying.

Unlike some here, I have no problem if I come across as a microshaft hater.  Use Linux.  It works.