3 monitors not showing on 6950, using active DP...

[Sindree1]

I just got a new computer with Sapphire Radeon HD 6950. And got 3 monitors now, so I want them all to show as seperate extended windows with their own resolution.

The 6950 had a miniDP to DP converter, and I bought a HIS active DP to DVI adapter.

So what I got plugged in now is:

1 x Dual-Link DVI on the 6950 - single link dvi cable - monitor
1 x Single-Link DVI-D on the 6950 - single link dvi cable - monitor
1 x Mini-DisplayPort on the 6950 - adapter to normal DP witch came with the card - HIS dp to dvi single link (active) adapter - single link dvi cable - monitor

This is the adapter I bought:
http://www.hisdigital.com/un/news_show-131.shtml
http://www.hisdigital.com/un/product2-567.shtml

This should work, but it doesnt. And I have no clue why, help please?

[matrices]

What is and what is not working, exactly? Which connection?

[jeroen94704]

Are you sure that is an active adapter? I have pretty much the exact same setup, and it works for me. The only differences are:

- I use dual link DVI cables on the actual DVI ports. No big reason for this, those are simply the cables I had lying around
- I use the Sapphire DP to single-link DVI adapter: http://www.sapphiretech.com/presentation/product/?psn=0001&pid=357

Other things that come to mind:

- Try a different DP port
- Make sure all your monitors are set to DVI input (auto-detect doesn't always work)
- Install the latest Catalyst drivers, and go through the display settings dialog (including the "detect monitors" option).

Good luck,

Jeroen

[Picturesports]

I'm having a very similar problem with a 6950

2 IBM panels connected to the DVI ports and they work fine. To get the Chimei 221D working with them I got a mini-DP adapter.

Catalyst will let me select any 2 from the 3 but insists that one of the 3 must be deactivated. Cannot get all 3 working at the same time.

Interestingly the 221D connected to the DVI port comes up as a non-PNP monitor and fixes the resolution at 640x480 - it will only work on the mDP

Very annoying - Any ideas anyone ??

[jeroen94704]

I'm having a very similar problem with a 6950
2 IBM panels connected to the DVI ports and they work fine. To get the Chimei 221D working with them I got a mini-DP adapter.
Catalyst will let me select any 2 from the 3 but insists that one of the 3 must be deactivated. Cannot get all 3 working at the same time.

Sorry to perhaps state the obvious, but again: Are you really sure this is an ACTIVE DP to DVI adapter?

The way this works, as I understand it, is that these cards can generate only 2 TMDS (See Wikipedia) signals at once, which is what DVI needs. When you connect a DVI monitor to a DP port through a PASSIVE adapter (which simply connects certain pins on the DP side to certain pins on the DVI side), the card must still generate a TMDS signal, which is then simply routed through the DP port. An active adapter, on the other hand, accepts a true DP (Non-TMDS) signal, which is then actively converted to a TMDS-type signal BY THE ADAPTER. This leaves the 2 TMDS channels on the card free for use with the DVI ports.

Or something like this anyway.

So when you can only use any 2 out of your 3 monitors, that is highly suggestive of your DP-DVI adapter being of the passive kind.

Apparently, passive DP to VGA adapters DO work. On the other hand, the Sapphire adapter I mentioned earlier is pretty inexpensive as well (I got it for 25 euros), and that is definitely active.

Jeroen



Jeroen

[DFischer]

I had the non-pnp issue. Ended up getting a new adapter and it fixed it. I guess there's a lot of bad adapters out there.

[Picturesports]

Thanks for the information. I'd raised a tech call with AMD asking for advice and got the same reply (amazingly I can google the answer after I know what it is - before then .... not a chance :oops: )

AMD replied

If the Display Port connected display is not using a native Display Port connection on the monitor the adapter must be an active adapter for the 3 displays to work, active adapters will typically have a connection to a USB port in addition to the Display Port and DVI connection.
If the adapter is passive the best you will get is 2 displays.

Now for the downside of the interrnet. None of the local shops are going to have an active adapter in stock. I'll need to order one and do the wait 3 days thing. Some days I miss the local shop that you always paid a little more for things in, but they had what you wanted over the counter.

Thanks for taking the time to reply ...

[DFischer]

You don't have a Fry's or anything?

Get this -> http://www.frys.com/product/6443972