Thinkpad T520, Optimus doesn't recognize DisplayPort

NethShady · n00b Joined: 10 Sep 2012 Posts: 2

Hey folks,

I recently bought a DisplayPort cable for my Thinkpad T520, in the hopes of attaching my big screen to it.
Sadly, it seems that the Port is not recognized; xrandr only shows me LVDS1 and VGA1 (DisplayPort should be HDMI1)
I have a dual-boot setup with Win 7, where the DisplayPort works flawlessly, so it's not a cable issue.
I am using Optimus via optirun/bumblebee, so most of my system runs on the Intel card (HD 3000) and only select applications are started with the NVidia card.
I have tried different things, such as enabling discrete graphics in the BIOS, but then my Gentoo (or maybe only X) refuses to boot outright.

Thanks in advance for any suggestions,

Neth

Gusar · Posted: Mon Sep 10, 2012 5:40 pm Post subject:

If you switch to the discrete card in the BIOS, you need to reconfigure your linux system, which is now configured to run on Intel.

The DisplayPort is probably connected only to the discrete card. To get it working when the machine is in Optimus mode, you'll need xrandr1.4. I don't think everything is ready yet for xrandr1.4. One piece of the puzzle (xorg-server-1.13) is released, but other pieces (drivers) aren't yet. Soon though.

NethShady · n00b Joined: 10 Sep 2012 Posts: 2

I see. That certainly makes sense. In that case, I'll have to wait for that xrandr update, since I don't want to run in discrete mode.
Thank you very much.

chrispa · n00b Joined: 27 May 2013 Posts: 2

I've just tried the new version (1.4) of xrandr and it didn't change anything.
The bumblebee project runs fine for me but no way to get the second screen working.
Would be really interested if you have a new solution.