T520 and WQXGA (2650x1600​) resolution with Active DisplayPor​t- DL-DVI adapter

Question

Howdy,
I'm seeing a lot of posts saying I can connect a T520 to a WQXGA monitor using an Active DisplayPort->DL-DVI adapter.
I've got a BizLink brand one which has been confirmed working. But when I use this with my T520 the maximum resolution it offers me is 2048x1536 (this is 4:3) resolution.
Is there something I need to do to get access the WQXGA resolution? I tried creating a 2560x1600 resolution but it just comes up with an error message saying it is not supported.

Answer 1

Well I just set my display to discrete (instead of optimus) and after some fiddling around I was able to get it working - both via displayport and my displayport->dl-dvi adapter.
I also tried to set it to integrated, but was unable to get it working. So I guess the intel video (or more likely drivers?) are the weak link here.
It's a little disappointing as I was hoping to still use optimus tech - although I haven't bothered to fully explore the settings (I am not familiar with the technology, I assume thre is no way to switch between integrated/discrete/optimus at runtime?) it wouldn't surprise me if this was not possible.
As an interesting aside I also had to physically power off the monitors I was playing with. As in, if I had connected to the monitor with my laptop in optimus mode, it would only offer me 2048x1536. After switching my laptop to discrete and booting back into windows, it would sitll only offer 2048x1536, even after plugging/unplugging the cable. I had to turn off the monitor (and additionally reboot laptop again, although not sure if this made a difference) before I could get QWXGA working.
It may be worth updating the knowledgebase article to include this information.