DisplayPort oddities

[Voodoo90]

R9 280x Outputs

Hello,
I have a kinda strange problem.
I am using Ozmosis and a R9 280X graphics card. So far I have used the DVI and the HDMI Out on the card. Without problems. But I wanted to enable the Sound on my monitor. And since DVI doesn't support sound, I want to connect it via DP. So I bought a DP cable.
Now the strange thing.
When I connect the HDMI and DP, nothing happens, I have a black screen on the monitor, only HDMI works.
When I connect only the DP nothing happens, black screen.
When I connect the DP and the other DP with a DP to HDMI adapter I have both screens working and I can enable the Display Port audio over the native DP cable to my monitor, but then HDMI audio ist not working anymore.
I need both, they are very important. How come the DP cable only works the adapter is connected.
How can I fix this? Buy a new cable? Anything else? On Windows it works just fine.

 

[Voodoo90]

Meanwhile I swapped my R9 280X for a Gigabyte Rev 2.0 version.
But still, I can use DVI on its own.
HDMI Output isn't working at all.
Display Ports work, but only if one is used for a HDMI adapter. I can't use one Display Port on its own for my main monitor.

Is there nobody, who can help with this?
I/O Jones says all 4 connectors a detected.
So where is the solution to this.
Best solution would be main monitor to DP and TV to HDMI, both with Sound.

I'd be thankful for every hinch.

 

[electrixx]

you guys are on mavericks 10.9.2?



i have a sapphire r9 280x, i lost my dual-dvi output with update to 10.9.2

i have 2 x 27" Monitors connected to both mini DP Ports, i get full resolution (2560x1440).

I did a few tests: if i connect just one monitor do miniDP, it has to be connected to the one next to hdmi output, second miniDP connector doesnt work alone (as second display it works then), DVI, DUAL-DVI and HDMI are not working anymore, while i have connected both 27" Screens to DP. Sound works over DP.

I am using clover bootloader and i had to enable ATIInject with AJI Framebuffer, noIPGU is enabled on my system.