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ATI HD 5450


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I am trying to install Mountain Lion on my IvyBridge system. I believe everything is working apart from the graphics and was hoping someone with a little more experience could shed some light on my problems.


The graphics card is Gigabyte Radeon HD5450 (GV-R545D2-512D)


I am using the stock ML kexts and have 3 screens.

At first the system just hung on boot but after I added my graphics card's device id to the Cedar part of the kext and in AMD5000Controller it can boot.

The problem is the screens are scrambled (sometimes colourful static, mostly big white blocks). You can see just as it loads the GUI the grey screen is fine and the mouse cursor is at the top right and drawn correctly, then about 1-2 seconds later it goes scrambled and you can kind of make out the rest of the GUI has been drawn.


I am using GraphicsEnabler=Yes and have tried all the personalities supported by the 5000 series. The different personalities do change which screen outputs are 'live' but they are always scrambled.


Interestingly I can boot in safe mode (-x) and the drivers appear to work (Eulemur) but only drives two screens. I don't quite understand why it works in safe mode I would have thought it would use the default VESA driver but the system identifier shows the correct card, kextstat show the AMD5000 driver is loaded etc.

Also in safe mode, while performance isn't great it may be acceptable and 2 of the screens are driven at the correct resolution (1080p) and have acceleration working.


Does anybody know what this screen scrambling might be? I though EDID but comparing the IODisplayEDID from ioreg -l in safe mode and ssh'd in when the screens are scrambled in normal mode are identical.


Also I need to be able to rotate the screens as they are in a portrait configuration, when in safe mode the rotation option is not present in the display properties. Again any advice?


Any help on this would be much appreciated :)

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I have made good progress on this issue...


By comparing kextstat from safe mode to normal mode I saw that both AMDRadeonAccelerator and ATIFrambuffer kexts were loaded in normal mode. I assume there is some conflict here because after moving AMDRadeonAccelerator out of the way I get three screens with no scrambling!

I'm not sure where AMDRadeonAccelerator came from - must have been from something I tried to get this working!


So the biggest problem is now overcome however I still have 2 issues:


- The screen rotation dropdown does not appear, I can't seem to find any information on why this would be?


- "3D" effects are quite slow chess / safari new tab, etc


PS: GraphicsEnabler=No doesn't appear to be any different than Yes now. Both have 3 screens, poor performance and no rotation

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Thank you. You're absolutely right.


I'm not sure what had happened to my kexts but I guess I had messed them up trying a million different things to get it to work.

I reinstalled OS X from scratch and simply added my device-id to the kexts and everything is fine.

3 screens with 3D acceleration and rotation.

Performance is not fantastic but I guess this GPU is somewhat underpowered for OS X, it is certainly acceptable though.


Thank you again for your help.

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