07-03-2011 09:46 PM
When my T520 is docked in a ThinkPad Mini Dock, I am unable to get the boot or bios displays to show on a DVI monitor attached to the Mini Dock. During a normal boot with the ThinkPad docked and lid closed, I can "blindly" enter the Hard Drive password and the T520 will boot normally and Windows uses the DVI monitor just fine.
Going into the BIOS setup (T520 is docked but need to use the laptop screen) the Boot Display Device option only shows choices for "ThinkPad LCD" or "Analog (VGA)". There is no "Digital 1" or "Digital 2" choice as mentioned by the help text.
My T520 is model 4239-CTO
BIOS is level 1.21
ThinkPad Mini Dock Plus Series 3 is 4338-30U
Thanks in advance for any tips on making this work.
07-04-2011 04:44 AM
07-06-2011 08:44 AM
Thanks for the tip about turning off Optimus. I found this combination of BIOS settings will enable the BIOS Boot Display Device option to show a choice for a the dock-attached DVI monitor:
Graphics Device -> Discrete Graphics
EnableOS Detection for NVIDIA Optimus -> Disable
However, I believe these settings will cause the Discrete Graphics Device to always be enabled ( ? ) Therefore battery life will be impacted when not docked and running on battery ( ? )
It seems unfortunate there isn't a way to set Graphics Device to "Discrete" when docked and "Optimus" when undocked.
07-06-2011 08:48 AM