Thinkpads Forum

Not sure if this has been mentioned before - feel free to delete if it has, but I have today successfully hooked up my T400 through the DVI-D port on the advanced mini dock (2504) to an external monitor. I state this because there appears to rumours and problems on the internet and also on Lenovo's actual site saying this isn't possible. I can only imagine its not possible on integrated graphics if you've got a T400 with the switchable graphics, mine is integrated only and it worked fine!

Hope this is of use.

That's right. Only 1 graphics chip is hooked up to the DVI on the dock. If you have ATI graphics, then only the ATI can drive DVI. If you only have Intel - then the INtel drives the DVI.

Ahhh well that explains it! Hope people hit this site when looking in the future - thanks for confirmation.

I am confused. I am about to order a T400. I want to be able to use the advanced mini dock to conenct to 2 monitors 1 DVI and 1 VGA . Will this work. I am ordering the T400 with switchable graphics.

Yes - as long as you are in Discrete Graphics mode when docked. Your built-in LCD will go dark.

awolfe63 wrote:Yes - as long as you are in Discrete Graphics mode when docked. Your built-in LCD will go dark.

Probably a dumb question but I haven't yet played with switchable graphics, but can I just set up the correct profile in my presentation director?

I don't know - I use XP and select graphics modes in BIOS.

I think we should not assume that the switchable graphics does not let the integrated chip access the DVI port on the dock.. here's why:

I am dual-booting linux and windows (still have annoying suspend/resume bugs in linux whatever I try).. Anyhow. So I forgot to change it in the BIOS back to switchable graphics (from integrated) before going into Vista. I always get weird/semi weird behaviors when I'm booting in Windows and have been using the Presentation Director..

Sometimes, I get only 1 display on (displays black but you can have your cursor there and such) and the login screen is on another display, but it does not send signal to that display, so switching presentation mode back and forth with the shortcuts usually bring it back... but just a few minutes ago I got that problem and I ended up getting a signal on my right screen (plugged in via DVI on my advanced dock) while being on the integrated graphics. Once I logged in it changed to my left display which is plugged in via VGA on my dock, and then the drivers would tell me it cannot use DVI... yet it did use it before I was logged in.

So I believe it is a software limitation more than a hardware one.. Either that or Windows ignored my BIOS settings and used switchable graphics while the selected option was Integrated controller...

I would bet on the last situation. The DVI-drivers are inside of the ATI chip and it's really hard - possibly undoable - to connect two sets of DVI drivers directly together outside of the chip and get it to work.