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New Macbook Pro 17'': Detect Displays fails after sleep Laptop Macs
Today I noticed that the external display attached to my new 17" MacBook Pro Core i7 is not recognized any more after I put the system to sleep by closing the lid. The 'Detect Displays' command from the Displays menu or the Displays preference pane didn't work. Rebooting the system is a possible solution, but not the preferred one.

I tried out some things and then searched some forums, but found no working solutions. Then I remembered that little tool GfxCardStatus from Cody Krieger and fired it up. I switched the active graphics card by selecting 'NVIDIA only' and then hit 'detect displays' and immediately the MacBook Pro detected the external display.

I did a little more testing and could reproduce the behavior; I switched to the Intel card by selecting 'dynamic switching' in GfxCardStatus, put the Mac to sleep, woke it up again and once more the display was not recognized. Now I switched back to the NVIDIA graphic by starting iPhoto (you can see that NVIDIA is active with GfxCardStatus), and the display was detected again. Aperture or any other software, that causes a switch to the NVIDIA card, should also work, I tried it with Aperture (which I mostly use in conjunction with the external display, which also explains why I not earlier noticed this issue).

[crarko adds: I haven't tested this one.]
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New Macbook Pro 17'': Detect Displays fails after sleep
Authored by: itistoday on Jun 05, '10 02:13:41PM

You should report this bug to Apple:

http://bugreporter.apple.com



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New Macbook Pro 17'': Detect Displays fails after sleep
Authored by: Ralph42x on Jun 06, '10 03:34:37AM

Ok - done! In the next future I will take a closer look into the "fixed bugs list" when a software update is coming from Apple!



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New Macbook Pro 17'': Detect Displays fails after sleep
Authored by: tiktak on Jun 06, '10 10:01:51AM

The "bug" you mentioned is not a bad one. The only way to display stuff just on your external screen is to close the lid... wait a min or two then click on a usb mouse or something similar then nothing gets displayed on ur laptop! This is particularly useful for me because the resolution on my laptop and the external screen are different... So i guess it is a bug of sorts but if they "fix" this then we'll have no way of using just the external display. To be honest they should have added this feature in the first place!



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New Macbook Pro 17'': Detect Displays fails after sleep
Authored by: anthony11 on Jun 08, '10 09:23:58AM
This is particularly useful for me because the resolution on my laptop and the external screen are different Assuming that you mean that the pixel count is different (resolution means something different), so what? The external should only be constrained if one has it mirroring the built-in, no?

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New Macbook Pro 17'': Detect Displays fails after sleep
Authored by: felix-fi on Jun 07, '10 11:07:27PM

I confirm the problem on my brand new MacBook Pro 15" . However, it is not clear if Apple will fix it. After all, are we allowed to "block" which card is used (using gfxCardStatus).... or by doing so, we should remember that the screen configuration will be blocked too.



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New Macbook Pro 17'': Detect Displays fails after sleep
Authored by: lsequeir on Jun 09, '10 02:27:24AM

While I feel that you are indeed facing a bug, I just want to point out that it is not universal. I have used my new corei7 MacBookPro 17" with two different external monitors and a projector and so far (knock on wood) I have not experienced this bug.

It may be that for some reason your mac is not properly switching from one gpu to the other when it should.

---
Luís



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New Macbook Pro 17'': Detect Displays fails after sleep
Authored by: bellmyer on Jul 09, '10 08:24:32AM

I'm also having this problem, and it just started in the last week or two. I've spoken with apple and HP (the manufacturer of my external monitor). Apple was helpful, HP was the worst, but at the end of the day I still have the problem. Forcing the card to nvidia didn't help, nor did these two Apple suggestions:

Reset the System Management Controller (SMC):
- Turn off your system.
- Press Shift-Control-Option-Power.
- Nothing will appear to happen, but the reset was done.
- Restart.

Reset the PRAM:
- Restart your system.
- Before the gray screen appears, hold down Command-Option-R-P. (as in the letters, R and P)
- The gray screen will appear, chime, and then go black as your computer restarts *again*.
- Keep holding the keys down until the 2nd time the gray screen appears and chimes, then you can let go.

None of these solutions worked for me, but they're working for other people so I thought I'd post them.

With my system, I can kill the 2nd monitor just by clicking "detect displays". Reboot, external monitor is fine. Detect displays, monitor loses signal. Like clockwork.

A couple days ago I thought I had it fixed. My external monitor recommends 1366x768 resolution, but I noticed my settings were for 1360x768. I made the change, and was able to go in and out of sleep mode no problem. But that's not working now.

In the interest of helping others as well, I did switch out monitors briefly during my "try everything" blitzkrieg the other day. I'm wondering if that temporary switch helped at all. I'll have to try it again.



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