Anyone have trouble using switchable graphics while docked?

[jc321]

I have a T-400 and an advanced mini-dock with Digital and VGA cables attached to a Lenovo monitor.  I cannot switch graphics cards while docked.  It tells me to close 3D or video apps and disconnect external monitors. 

When not docked switchable graphics works fine.   I have Vista Ultimate.

Any ideas?

Thanks,

JC

[zilla]

Integrated graphics mode does not support DVI in a switchable graphics environment -- see here.

Message Edited by zilla on 2009-03-10 03:45 PM

[jc321]

Yep that part I was aware of.  I just seems odd that I can't switch to Discrete graphics when there is a DVI monitor attached.  I guess this is "explained" by the awkwardly worded -

<* If only a DVI or DisplayPort device is connected, the integrated device cannot detect these devices and will permit a switch to High Performance mode.>

Which implies that if both DVI and VGA are attached, it cannot not switch the graphics cards.   This is beyond lame and renders mini-dock usage problematic.

Regards,

J

[zilla]

You can't switch to integrated mode with the DVI cable attached and that asterisked footnote says you can't switch to discrete mode with the VGA cable attached.

[jc321]

That, them, there, is some quality engineering. 

Message Edited by jc321 on 03-11-2009 08:55 PM

[Unicorn]

@jc321:

this is a feature not a bug, since DVI in mini-dock is supported only using discrete graphics ...

Cheers

Unicorn

[jc321]

Hi Unicorn -

No, it's most definitley a bug.

Use case: 

I use laptop with integrated graphics to save battery while on the road.  At days end, I go home and attach laptop to docking station.  Attached Monitor (and dock) has VGA and DVI connections so it will display the VGA feed.  Want to use DVI at this point.  Can I switch cards at this point?  Ummmm...No.  One has to make the switch while on the road.  

Message Edited by jc321 on 03-12-2009 11:29 AM

[zilla]

My Thinkvision monitor has a hardware switch allowing you to choose DVI or VGA when using dual cables. What happens if you in integrated graphics mode using your monitor in VGA, switch the monitor to DVI first? According to that footnote the T400 should no longer recognize there is an external monitor attached so allow the switch to discrete mode. And if it no longer recognizes there is an external monitor wouldn't it automatically turn on its own LCD screen so you see what you are doing when going to the power manager for the graphic mode switch?

Sorry I can't test as I am using the modded ATI driver at the moment (see the voluminous display driver "amdkmdap" crashes thread.)

[jc321]

Doh! why didn't I think of that?  As it turns out this doesn't work either However, you got me thinking and you're really close.  First you have to dock with the laptop open (I never do this and will spill something on the machine shortly as a result)  You make the change via Fn-F7 to laptop LCD only, then switch cards, then switch back to the monitor.   Not ideal but it works both ways. 

Thanks,

JC

[zilla]

The T500 has different setups for battery and ac power for action taken when closing the laptop. So with do nothing set when on ac power you can dock with the laptop open and then close it.