T400 - Why can't I use DVI in mini-dock with integrated graphics?

Hey all...

So I just tried out my mini-dock for the 1st time, while using integrated graphics, and found that the DVI port - hooked up to an external monitor - wasn't registering as being attached to anything.

So I did a little research and found someone who said that the DVI in the dock only works if you're using the discrete graphics.

This seems kind of strange to me - I have 2 older thinkpads, both of which were able to use a dock's DVI port, and one of which had integrated graphics only. I thought the point of the DVI in the dock was to be able to use DVI, whatever graphics chips/cards you were using in the Thinkpad.

Does anyone know which is true?

- Tim

 

I've read conflicting posts around the internet about whether this would work or not. Some claim that it should still work with integrated and other say only with discrete. I imagine the T400 specific dock which Lenovo plan to release (but who knows when) will have this option availble as the Intel integrated graphics are capable of this.

 

I can't tell you why… but it's a known and documented limitation of the technology. See Switchable Graphics Frequently Asked Questions (FAQ) on Lenovo's web. It's still a nuisance though.

 

Been thinking about this and surely it could be resolved with a bios update? Are you running the latest BIOS?

 

Hey,
my BIOS version is 1.16. The latest BIOS available on lenovo.com is 1.15. Don't know how that works, but i should have an up-to-date BIOS then, right?

GoMike

 

Hi there. Just thought I’d report back that I have successfully connected through the DVI port on the advanced dock to a monitor using my T400 on integrated graphics. I did some research and posted here:
http://forum.thinkpads.com/viewtopic.php?f=45&t=72234 But basically you should be able to use the DVI port if you have integrated graphics. If you have switchable graphics you need to use the ATI chip (the discrete chip) to run the DVI. Good news to all of those who thought that their T400 with integrated graphics chip couldn’t DVI out from the dock – YOU CAN!!! (especially annoying since Lenovo’s website even states you can’t).

 

For the T400/500s shipped with an ATI graphics card there are three possible settings for the display in BIOS setup (F1 when booting), each with its own set of drivers:

1. Integrated. Only the Intel integrated graphics visible in the device manager. Standard Intel driver used.

2. Discrete. Only the ATI graphics card visible in the device manager. Standard ATI driver atikmdag used.

3. Switchable. Support for both graphics cards and hot swap between the two. The hot swap is made from the switchable graphics submenu of the power manager. (Left or right click on the battery icon dependent on its release to find the submenu.) In this submenu the Intel integrated graphics are called energy savings graphics and the ATI graphics card high performance graphics. Both settings use the ATI switchable graphics driver amdkmdap.

3a. Energy savings graphics. Only the Intel integrated graphics are visible in the device manager.

3b. High performance graphics. Both the Intel integrated and the ATI graphics cards are visible in the device manager.

DVI is supported in environments 1, 2, and 3b. Only 3a does not support DVI. The referenced Lenovo F.A.Q. is an F.A.Q. for switchable graphics, ie covers 3a and 3b only.

 

Hey,
that's interesting now. As far as I know, you cannot use DVI with the integrated graphics when you have both chips (ATI and Intel) build in to your laptop.
Am I overlooking something or is it now possible to use DVI while you have selected "integrated graphics" in your BIOS? Where did you get your information from, zillal?

GoMike

 

Hi GoMike, where do you have your information from?

The BIOS setting is a HARDWARE switch, once it's set to integrated there is nothing that distinguishes the T400/500 from one shipped with Intel graphics only.

 

I tried it a while ago and it didn't work.

Did you try to use your DVI while you're on integrated graphics and did it work? What did you do?

GoMike

 

The Vista switchable graphics driver isn't that easy to get rid of. It sticks around until you reboot in Bios integrated mode, let the standard driver load, reboot again AND then do the same rebooting twice for Bios discrete mode.

With Vista 32 and 4GB memory I can see in the performance tab of the task manager (ctrl-alt-delete) when it finally gives up and releases the 0.5GB it's been hogging, giving me back 3GB usable memory instead of 2.5GB.

Don't know if this whole procedure is necessary to get DVI to work in Bios integrated mode and I am not going to experiment as i think that would force me to reinstall my modified ATI drivers in the Bios discrete mode afterwards, see this thread.