I am currently working on getting a 2 Screen setup to work with my system. I have a recent 27" Shimian QH270 (DVI) with 2560x1440 max. and a pretty old MEDION MD7218AR (VGA) with 1280x1024 max.
The very first step was to make my ports work. For this I edited my Duckweed Personality after reading Alexander Martinez' Guide, and bcc9's Thread. My first problem was I had no Windows Partition and no HDD lying around. Tried for days to get almost every Windows working on externals without luck. Then stumbled upon this Guide from rampagedev which is basically a round-up of all the others and went for the DOS way. When I was already set up to work my way through all personalities I found fffeee's Post who has exactly my card. So I thought I'd give it a try and just edit my Duckweed as he did.
This is the as-is for now. My DVI Ports both work, which is what I needed. (Can't even test HDMI and DP)
[ DVI-I(DL) ]✔ [ HDMI ] [ DP ] [ DVI-D(DL) ]✔
When I connect the DVI-D Cable of the 27" to the DVI-D Port I don't get support for no-VESA resolutions (which is 2560x1440). When I connect it to the DVI-I Port, the Screen gets full resolution support.
This is troublesome, since I have no chance to connect the VGA Adapter to any other port than the DVI-D.
I came across this thread about VESA modes but it actually refers to the boot screen only. I did try to edit my ROM and load it with AtiROM=Yes but failed in editing I suppose since system didn't even load.
Custom DSDT GraphicsEnabler=Yes AtiConfig=Duckweed AtiPorts=4 GraphicsMode=2560x1440x32
1) Is there anybody out there with a) experiences with similar cards + edited framebuffers + screen sizes or even with B) similar working setups?
2) Do you have any ideas/tips for me on what to work on to get support for the desired resolution on that port? (VESA/Framebuffer/Other?)
Mainboard: GA-H77-D3H (EFI F10) CPU: Intel Xeon E3-1230V2 GPU: Sapphire HD6870 1024MB (Barts XT RV940) GPU VenID: 1002 GPU DevID: 6738 GPU SubSysID: 174b OS: 10.8.3 (12D78)
For further input I can post more details if necessary. Hope anybody has some ideas floating in their head.