Tahiti LE 7870 graphics card, black iMac screen in target display mode

[Detosx]

I bought a Belkin mini display port to mini display port cable to use a 2010 27" iMac's screen in target display mode with my Hackintosh via a VTX3D HD7870 Tahiti LE card, in other words basically a partially crippled HD 7950. For some reason, just before where the login screen would otherwise appear, the iMac screen goes black/blank. I wonder if anyone here has got a 7870 Tahiti LE card to work in target display mode with an iMac or if I am fresh out of luck? Perhaps there is a list of graphics cards known to work/not work. I didn't have much luck searching.

 

[Detosx]

I spotted a thread "mini displayport not working on Radeon 7970 - Mavericks" and found a solution, thanks to forum user electrixx. It is working for me, so far, with no problems with VLC or Youtube. I will try other frame buffer personalities to see how well they work but meantime Aji, inserted into my Clover boot loader's config.plist, seemed to do the trick. See link below.

http://www.tonymacx86.com/graphics/...working-radeon-7970-mavericks.html#post777485

 

[Detosx]

Further to the above, I found it worked with Mountain Lion, also, but that I needed to do the good old sleep trick. When the computer boots as far as it will to a blank screen, depress power button to drop computer into sleep... wait fifteen seconds or so... depress power button again and this time the login screen, or desktop if you don't have a log in screen, comes up.

 

[Detosx]

Early days, yet, but I installed 10.9.3, today, and I find I still have to use the Aji frame buffer personality in my Clover bootloader's config.plist or I am left with a black screen where the login screen would be. Some people had suggested that would no longer be needed when 10.9.3 came out. If I find a way to get it working without, I will report back.

 

[Wundorn]

Detosx,

Can you tell me more about how you set up your machine? I too have a Tahiti LE 7870, and I've found some very odd behavior in 10.9 - so much so that I've stayed on 10.8 so far. In particular, it gets recognized as a D500, but the performance of the system in various benches and games is identical to the performance of the builtin HD4000 graphics. On 10.8, I get the expected (way better) performance.

This was only tested in 10.9.2 - I haven't had the energy to try 10.9.3 yet. MB is Gigabyte Z77-DS3H, exactly as recommended here during the Sandy Bridge days.

 

[Detosx]

Hi Wundorn, do you use Clover as your boot loader? I can share my config.plist and bios settings with you, though I can't guarantee it will work with your setup, so I am reluctant to share it outside of a GA-Z77MX-D3H-TH thread.

The key part in my config.plist for my card is this. I had to phrase it in this way rather than just insert the values into the default config.plist or it wouldn't work with my set up.

 

[Wundorn]

Hi Wundorn, do you use Clover as your boot loader? I can share my config.plist and bios settings with you, though I can't guarantee it will work with your setup, so I am reluctant to share it outside of a GA-Z77MX-D3H-TH thread.

The key part in my config.plist for my card is this. I had to phrase it in this way rather than just insert the values into the default config.plist or it wouldn't work with my set up.

I have not been using Clover, so far. I had hoped to avoid learning too much about this - I spend enough of my life on hacking, professionally - so I went totally plain-vanilla until I bought this card. That means standard unibeast/multibeast. And everything worked fine in 10.8.x (except imessage, argh, that's endless grief).

Can you confirm that your 10.9 is giving you proper performance with the Tahiti 7870?

Anyway, thanks for your info. Sooner or later I will have to dive in & figure this out. Oh well, ignorance was bliss, at least for a while.

 

[Detosx]

The few people I found who got it working were using Clover, also, so I don't know about other bootloaders but the important part is Aji. If you do a search for Chimera or Chameleon with Aji, you should, I think and hope, find someone with the correct plist entries. As to performance, what were you using for benchmarking?

 

[Detosx]

I just updated to 10.9.4. I am a little disappointed to say I still need to have Aji as Framebuffer personality in my config.plist or I'm booting into a black screen. All seems to be working well, otherwise, and even feels a little snappier.

 

[toleda]

I am a little disappointed to say I still need to have Aji as Framebuffer personality in my config.plist

If the default framebuffer does not work, Aji is your best choice. Specifying a framebuffer ensures the graphics card is fully recognized and enabled. Changes to framebuffers are rare after initial release. Given the difficulty in getting AMD graphics to work in OS X, enjoy your success.