Why does daisy-chaining a Mini-DisplayPort monitor in a Thunderbolt chain cause overscan issues?

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Level 1

4 points

Why does daisy-chaining a Mini-DisplayPort monitor in a Thunderbolt chain cause overscan issues?

I have the awkward 2011 MacBook Pro with a single Thunderbolt port and no USB3. I very frequently use it connected to my HP 2311x LED Monitor. For the very first time, today I placed a external Thunderbolt drive in-between my MacBook Pro and the HP 2311x. This causes the image to severely overscan. Correcting it by using the underscan option in the display settings significantly reduces image quality.

MacBook Pro (15-inch Late 2011), OS X Mountain Lion (10.8.3), HP 2311x LED Monitor

Posted on Apr 26, 2013 6:32 PM

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Answer 1

Apr 26, 2013 6:40 PM in response to smackies

See if the Thunderbolt Display and Port article help...order do connection is important... http://support.apple.com/kb/HT5219

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Answer 2

smackies Author

Level 1

4 points

Apr 26, 2013 6:46 PM in response to Ralph Landry1

They're connected in the correct order: MacBook Pro > G-RAID Thunderbolt > HP 2311x. And the monitor works, too. The issue is that the image quality is terrible and it overscans the display.

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Answer 3

Apr 26, 2013 6:59 PM in response to smackies

Two more of interest:

http://support.apple.com/kb/PH11407

http://support.apple.com/kb/PH11409 which also says if a device works properly by itself, but then not correctly after the TB device, there may be a problem with the TB device.

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Answer 4

smackies Author

Level 1

4 points

Apr 26, 2013 7:13 PM in response to Ralph Landry1

There's nothing wrong with the Thunderbolt device. My two best guesses are that there's something wrong with the Mini-DisplayPort to HDMI cable or with Apple's display drivers. I just plug a Mini-DisplayPort to HDMI to DVI adapater with a DVI cable into the Thunderbolt drive, and now everything works. It's not exactly solving the problem, but at least it works.

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Answer 5

LowLuster

Level 6

12,105 points

Apr 27, 2013 2:44 AM in response to smackies

So your monitor has both DVI and HDMI ports. Then you might think about getting just a thunderbolt to DVI adapter to cut down on the connection points.

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