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10-27-2010, 08:26 PM | #1 |
Junior Member
Join Date: Oct 2010
Location: New Zealand
Posts: 3
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Broken display; snow stripes ghosts using DisplayLink & MacBook Pro i5 i7 15/17 inch
Many people are having trouble with 15 and 17 inch MacBook Pros (MBP) with i5 and i7 processors when there is no external monitor plugged in — not by the USB DisplayLink adapter nor the Mini DisplayPort (MDP) (i.e. with a DVI or VGA adaptor).
I've spent several hours testing and debugging this as well as reading through bug reports from other people on this forum and thought that this summary would be helpful for others. This bug causes the MBP's display to have snow, stripes, random patterns or other graphics that render the display unusable when the following criteria are all TRUE;
I have simply explain the technical nature of the bug below, but if you just want a quick fix, any one of the following should fix or workaround the issue;
The i5 and i7 MBPs ship with and use both heavyweight and lightweight GPUs (in i5 and i7 MBPs, these are "NVIDIA GeForce GT 330M" and "Intel HD Graphics" respectively), and OS X 10.6 is able to seamlessly switch between them to save energy and extend battery life when processing power is not needed. The MBP will always use the lightweight GPU unless any of the following are true;
Most of the suggested workarounds above only prevent the MBP from switching to the lightweight GPU. This means that if you use one of these workarounds, the MBP will consume about 11% more power than it would if you uninstalled the DisplayLink driver, unplugged anything from the MBP's MDP and turn "Automatic graphics switching" on. So turning "Automatic graphics switching" off is a good workaround for almost all use-cases. However you may wish to uninstall the DisplayLink driver and turn "Automatic graphics switching" on if you are expecting to need longer battery life (such as on a long flight) and are not using graphics-heavy applications. The real fix for this bug is up to Apple. August 17's Snow Leopard Graphics update changed some of the symptoms of this bug, but did not fix it or reduce it's severity. The bug is reproducible with or without the update. |
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