Display going to sleep unexpectedly (and does not wake)

Question

Display going to sleep unexpectedly (and does not wake)

I'm recently having an issue on my Mac Pro (Mid 2010) where my external displays will unexpectedly go to sleep and then will not wake up afterwards unless I force shut down my computer and reboot from scratch.

A few details are:

The Mac is still on in the background, so it's only the displays that have gone to sleep
It will sometimes happen as soon as a few minutes of use and sometimes after an hour. Sometimes if it's in mid-use and others if it's been left for around 5-10 minutes. It literally seems to be random.
Using Command+Control+Power button to restart does not bring the display back. The computer needs to be shut down completely and turned on again for the displays to work again. Using Command+Option+Control+Power to shut down only occasionally works so often need to force shut down.

A few things I've tried:

Disconnecting one of the two displays
A PRAM update
Disconnecting the power for a period of time then reconnecting.

I expect I need to see an AppleGenius, however the MacPro is pretty heavy to take on the train with one person and as I say, it can take a while for it to occur so there's no guarantees it'll happen in the store itself.

Has anyone had a similar issue or can think of a potential fix? I am running Yosemite and might be worth mentioning that I am using an ATI Radeon HD 5870 1024 MB graphics card (which was upgraded from the standard at the time of purchase).

Thanks you

Mac Pro, OS X Yosemite (10.10.2), ATI Radeon HD 5870 1024 MB graphics

Posted on Feb 19, 2015 1:13 PM

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Answer 1

Linc Davis

Level 10

209,541 points

Feb 19, 2015 1:16 PM in response to halo_fourteen

Please read this whole message before doing anything.

This procedure is a diagnostic test. It’s unlikely to solve your problem. Don’t be disappointed when you find that nothing has changed after you complete it.

The purpose of the test is to determine whether the problem is caused by third-party software that loads automatically at startup or login, by a peripheral device, by a font conflict, or by corruption of the file system or of certain system caches.

Disconnect all wired peripherals except those needed for the test, and remove all aftermarket expansion cards, if applicable. Start up in safe mode and log in to the account with the problem. You must hold down the shift key twice: once when you turn on the computer, and again when you log in.

Note: If FileVault is enabled in OS X 10.9 or earlier, or if a firmware password is set, or if the startup volume is a software RAID, you can’t do this. Ask for further instructions.

Safe mode is much slower to start up and run than normal, with limited graphics performance, and some things won’t work at all, including sound output and Wi-Fi on certain models. The next normal startup may also be somewhat slow.

The login screen appears even if you usually login automatically. You must know your login password in order to log in. If you’ve forgotten the password, you will need to reset it before you begin.

Test while in safe mode. Same problem?

After testing, restart as usual (not in safe mode) and verify that you still have the problem. Post the results of the test.

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Answer 2

Feb 19, 2015 1:40 PM in response to Linc Davis

Thanks for this.

Interestingly, when booting in safe mode, the display will immediately disappear after the progress bar has been completed. This is with all unnecessary cables plugged in (my keyboard and displays only remain).

This being said, I do have an additional PCIe card plugged in, but I won't be able to remove this until the weekend as it's a little more tricky and is getting quite late where I am.

I then rebooted into normal mode and display was fine but disappeared very quickly after. Shall I confirm after removing the PCIe, or does this provide you with enough info?

Thanks

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Answer 3

Feb 19, 2015 1:41 PM in response to halo_fourteen

Sorry to confirm my error above - all unnecessary cables are removed (only the keyboard and displays remain).

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Answer 4

Linc Davis

Level 10

209,541 points

Feb 19, 2015 2:59 PM in response to halo_fourteen

You would have to remove the card in order to know whether it's causing the problem.

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Answer 5

Feb 22, 2015 9:27 AM in response to Linc Davis

Thanks for that. I did some more test and managed to round it down.

It seems that if I go down to just one display, everything works perfectly, however if I add a second display, then there are issues. I did a bit more reading and it seems that this is related to the Radion graphics cards on the Mac Pro.

See Re: iMac mid 2010 graphics issues after installing Yosemite

It's not limited to mine, seems there's issues with the Radion 7950 too: 2009 Mac Pro will not boot with the Apple 27" LED Cinema Display and 2010 Mac Pro + Yosemite + Radeon 7950

Interestingly for me, it this has only begun after I upgraded from OS 10.10.1 to 10.10.2, so it seems there's something in the latest OS X that has caused this to occur.

Any thoughts? I guess we need to wait for Apple to resolve this, which may not happen 😟

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