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I run two computers with double monitors through an Aten KVM. The kvm has only VGA input/outputs. One of my new computers has a VGA and a DVI-I adapter so no problems here. I use a DVI-VGA converter and 2 vga cables to the KVN.

The second computer has a VGA and a HDMI output, so I bought a HDMI-> VGA converter and connected it to the KVN. Everything runs as expected. I get good picture on both monitors and both computers BUT, when switching sometimes (very often) the monitor connected to the HDMI adapter forgets the resolution and is switched to a very low one. I need to switch back and forth several times and with little luck I get the normal resolution back.

I think this is an issue with HDMI handshaking, but I don't know how to solve this. Latest drivers on everything. Any ideas?

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up vote 1 down vote accepted

You'll want to get an HDMI-aware KVM.

ATEM makes some (for example):

Specifically in their product blurb for those, they seem to have a specific feature related to the problem your experiencing:

The ATEN HDMI KVM Switches provide enhanced independent switching via front panel pushbuttons and keyboard hotkeys, and features Video DynaSync™ technology to ensure that HDMI display resolution is always optimized.

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You don't need to buy another new Aten HDMI KVM switch.

The issue should be caused by the HDMI-to-VGA converter which is not passing correct EDID information (most of the converters in the market have EDID issue).

All you need is a "VGA EDID emulator with built-in signal terminator".
Put the VGA EDID emulator between you KVM VGA and your system's VGA.

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