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 I’m sure I won’t 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 don’t 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. Don’t 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 I’ve tested. The Apple one will work in some
cases, but you don’t know for sure till you try, so it’s most likely safer to
get the StarTech one. I’m 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 I’ve
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 “Non Plug and Play” 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