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Mini-DisplayPort on New Dells: Resolving issues with output to projectors in Windows 7

Mini-DisplayPort on New Dells: Resolving issues with output to projectors in Windows 7

 

    Hopefully this will be helpful for those buying new laptops, as Iím sure I wonít be the only person around that will run into this problem in the near future with Windows 7 and VGA Min-DisplayPort adapters from Apple.

TL;DR version for those that donít care about the tech: If you buy a new Dell laptop which you plan to put Windows 7 on, check to see if it has a VGA port or a Mini-DisplayPort. If it only has a Mini-DisplayPort you will need an adapter to connect to most of the projectors you are likely to encounter which take a VGA connection. Donít bother with the one from Apple, it seems to fail on many projectors when using Windows 7. Buy the StarTech model MDP2VGA, it seems to work without issue from what Iíve tested. The Apple one will work in some cases, but you donít know for sure till you try, so itís most likely safer to get the StarTech one. Iím not sure on other brands like MonoPrice yet, but would like to hear reports.


Tech Stuff: I recently got a new laptop, a Dell XPS L502X. It had not occurred to me to check to see if it had a VGA port, as all the laptops Iíve ever owned have had one up till now. Well, I got it and it had no VGA port, which is a problem for me when I go to do presentations. After showing it to some colleagues, we figured out it had a Mini-DisplayPort, which up till now you would mostly only find on Mac laptops (which is why when you look around for a Mini-DisplayPort to VGA adapter, most of the ones you will find are from Apple). I went to my buddy to see if the Mac Adapter (Model MB572Z/A or A1307 depending on where you look) would function. Well, it did work on the monitor in his office, so I thought I was good to go. I went to a few conferences, and found out I could not get the laptop to connect to the projectors there (at least not in Windows 7, it would connect in Linux so I knew the adapter worked). There was also at least one at work that did not function. We even tried updating the firmware on the A1307 (yes, it has a firmware update), but it was already at the newest revision. After doing some playing around, I figured out it would not connect to a monitor or projector that did not send EDID or DDC2 info. I replicated this by ripping pin 12 out of a VGA cable. EDID and DDC2 are protocols your monitor/projector/display uses to tell the computer what resolutions it supports, along with other details. If you see a monitor in Device Manager that says ďNon Plug and PlayĒ it likely is not sending EDID/DDC2 information. The Dell XPS laptop would connect ok if I first hooked it to a monitor that supported EDID/DDC2, then unplugged just the VGA cable and walked it over to the non-plug and play projector to hook it up. I also borrowed an EDID emulator from a co-worker that man in the middles the VGA cable and sends a mock EDID signal, and then the Apple DisplayPort adapter would work with my Dell on a projector it would not work on before. Well, this EDID emulator is kind of pricey, and it along with a VGA cable takes up a lot of space in a laptop bag.

Solution: I ordered the StarTech model MDP2VGA Mini-DisplayPort toVGA adapter, so far no issues and it seems to work fine on a non plug and play projector where the Apple adapter failed. Hope this info helps someone.

 

I figured as long as I was saying good things about the product I might as well do a referral link. :)

Extra Details:
Since I'm not really sure how all of my components are interacting, and which part is really to blame, I figured I'd give folks more details on my system so they can replicate the issue. This may also help folks searching Google for the answer to their problems.

My Systems specs:
Dell XPS 15 L502X
CPU: Intel Core i7-2630QM
Video: NVIDIA GeForce GT 525M 1GB graphics with Optimus (Which means it uses two video chipsets, one for more intensive tasks and one that takes less power. This may be part of my DisplayPort issues.)

OS: Windows 7  Enterprise 64bit, SP1 failed with the Apple A1307, Linux worked. Not sure about other versions of Windows like XP or Vista, nor about the 32bit versions.

Adapter that failed:
Apple A1307 Mini-DisplayPort to VGA adapter (I've also seen people use the model number MB572Z/A)

Adapter that worked:
StarTech model MDP2VGA Mini-DisplayPort to VGA adapter

 

 

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