I want to achieve 2560x1440 resolution output from my laptop. I have a Dell XPS 15 (L521X) laptop on Ubuntu 16.04 and I want to output my screen to an external monitor from mini DisplayPort (laptop) to DisplayPort (BenQ GW2765 w/ 1440p). When I plug it in, the laptop screen & mouse freezes for ten seconds, and resumes, but the external monitor does not detect anything. I tried toggle display options (single, mirror, external, etc.) to no avail.
- The XPS has a dedicated Nvidia GeForce GT 640m + HD 4000 integrated graphics card.
- The cable is the latest Cable Matters Gold Plated Mini DisplayPort (Thunderbolt Port Compatible) to DisplayPort Cable, Black, 6 Feet (101007) from Amazon.
- I've connected the cable to a Macbook Pro's thunderbolt port and it works perfectly on the monitor at 2560x1440 resolution.
- When I connected HDMI to HDMI, it works fine, but only outputs 1920x1080 resolution. I really want the 2560x1440.
Any ideas on where to start or troubleshoot this?