Black Screen with iMac 17,1 Despite All Fixes

[EV.forever]

It did not work as I wanted it to on my own system

Sorry for asking for those before I had some more tests.


I'm not seeing this problem myself on 10.11.5, but I'm seeing it in a certain beta that we are not allowed to discuss here.

My testing seems to show that it is somehow related to the kernel cache (updated GraphicsDevicePolicy not getting added correctly to it).

No problem at all, thanks for this information. That would explain why none of the documented methods are working. They actually ARE working, but the kernel cache is preventing it from taking.

UPDATE:

Well, I tested my underlying assumptions about using 17,1 because I have the Skylake platform, and found them completely unjustified.

With results like this, I think I'm done trying to get 17,1 to work. Unless I'm missing something, even the power management appears to be the same.

The iMac 17,1 definition is working great with AGDP fix in macOS Sierra 10.12.3.

 

[cnrd]

I just did some more testing on my own system.

Do you have more than one monitor and how are they connected?

My problem disappeared when I stopped using the Dual-DVI port on my GFX (I had a DP to dual-dvi adapter laying around).

I have 2 monitors:
QHD270 (Korean 1440p Dual-DVI only)
Asus ROG Swift PG279Q (Display Port (DP))

Both of my monitors are connected to DP:
QHD270 -> Dual-DVI -> Dual-DVI to DP converter -> DP -> GPU
Asus ROG Swift PG279Q -> DP -> GPU

 

[EV.forever]

I just did some more testing on my own system.

Do you have more than one monitor and how are they connected?

Thanks again. One monitor, Samsung SyncMaster 2343 (VGA or DVI). I thought about trying DisplayPort but I don't have the adapter. It's just as well, I'm keeping this system on El Cap for the foreseeable future.

UPDATE:

I upgraded to Sierra. Works great!

 

[kiiroaka]

Where are you seeing the "Chipset+GENESYS LOGIC USB 2.0 Hub"?

You're right. That was probably on another motherboard. Your SATA3 channel 6 & 7 are on an ASMedia ASM 1061 chip, though.

You know how some guys say that OSX is not showing the correct mem speed? If you re-run with the latestClover you may see that OSX now will show the correct speed. If you then go back and re-run the MultiBeast Clover the mem speed shouldn't change back to 1333. Why? Because they were saved in the Kernel Caches. So if a configuration is giving you problems you will probably need to flush the Kernel Caches before running Clover again, just as you would need to wipe out the disk before re-installing OSX through MultiBeast. So, that may be an option - clearing the kernel caches before re-running MultiBeast and changing the MAC ID type.

I just wish that I had bookmarked the El Cap help file that showed how to flush the Kernel Caches. All I can say is that it worked for me when I couldn't get the nVidia WebDrivers to install correctly and when I couldn't get a Clover setting to stick.

 

[korgo]

Exact same problem here. I have done everything to get 17,1 to work with my GTX960 card. Up to the point where I started to filled with all the possibilities to get to 17,1 my system ran great on 14,2.
So I am in the middle of reinstalling everything from scratch again... That#s faster than waiting for a solution over here. There doesn't seem to be much traffic these days
I wonder what the difference in power between a 14,2 and a 17,1 would be. Maybe I am waisting my time on marginal gains?

 

[korgo]

So if a configuration is giving you problems you will probably need to flush the Kernel Caches before running Clover again, just as you would need to wipe out the disk before re-installing OSX through MultiBeast. So, that may be an option - clearing the kernel caches before re-running MultiBeast and changing the MAC ID type.

That sounds like a possibility... I am hesitant to do so, however. Since I had to start from scratch again once already...

 

[korgo]

That's what I am doing right now, starting from scratch and doing ye olde 14,2. Only thing that bugs me is that I wouldn't have needed a skylake board if it runs on a Haskell profile...

Well...

 

[korgo]

Good to hear... Hope this time everything goes as smoothly as the first time (before the 17,1 issue)

EDIT: Up and running as 14,2 again. Won't touch 17,1 for a while. This screwed my entire Saturday.

 

[starchild2]

Did you ever get this resolved?

 

[korgo]

No. I didn't try, though. My machine runs fines on 14,2 and I keep it this way.