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HD6870 ATI Sapphire DVI VESA Shimian 2560x1440

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#1
Deridjian

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Hi everybody,

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) ]✔

My Problem:
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.

My Boot.plist
Custom DSDT

GraphicsEnabler=Yes
AtiConfig=Duckweed
AtiPorts=4
GraphicsMode=2560x1440x32

My Question(s):
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?)

My System:
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.
Greetings

Deri~

Edited by Deridjian, 02 May 2013 - 07:35 AM.


#2
TH3L4UGH1NGM4N

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It's more so an issue of one being a DVI dual link which supports resolutoins beyond the 1080p (1920x1080). When you plug your glorious pixel screaming screen into the the other DVI port which I assume to be the single link one you won't receive your full resolution because it tops out at 1080p. The following image below displays the difference between them.

Posted Image

#3
Deridjian

Deridjian

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Thanks for you thought. My DVI cable is a DL anyways tho. I couldn't even plug it into SL. Both DVI Ports on the Sapphire HD6870 are DL. (The upper one being DVI-I where I can plug the VGA adapter, the lower one being DVI-D [I corrected the table above; copy/paste is evil ._."])
I do get offered a resolution of 1900x1200 btw.

Edit:
After a bit of research (manufacturer specs & label on the card itself) I found out that the lower DVI-D Port on the Sapphire HD6870 1GB GDDR5 PCIE is actually a Single Link although it physically looks like a Dual Link on my model!
The physical layout of my model doesn't even exist on the Sapphire website...the linked version (which should be my model) shows two DVI-I Dual Link connectors on the fotos...which is just as much a lie regarding the actual specs.

Now before giving up on this: From my VBIOS decode I get
// Connector Object Id [3] which is [DVI_D]
encoder obj id [0x20] which is [INTERNAL_UNIPHY1 (osx txmit 0x11 [duallink 0x1] enc 0x2)] linkb: false
and
// Connector Object Id [2] which is [DVI_I]
encoder obj id [0x1e] which is [INTERNAL_UNIPHY (osx txmit 0x10 [duallink 0x0] enc 0x0)] linkb: false
which is the working Dual Link port.

Doesn't look all that different to me, other than the Transmitter being LINKA in both cases and a different encoder. If I hardcode this right, maybe I can tell the card that it actually DOES have a Dual Link connector on the lower DVI-D port?...

#4
TH3L4UGH1NGM4N

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Talk about bad misleading marketing >_>

On most 6870s i've encountered (I have one myself) one DVI is DL and the other turns out to be SL I'm yet to see one that runs both DL.

Telling it to do what it might not be capable of doing might be on the borderline of impossible.





Also tagged with one or more of these keywords: HD6870, ATI, Sapphire, DVI, VESA, Shimian, 2560x1440

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