Unable to get 4k Resolution with linux model S3221QS

Hi There,

I just bought a DELL S3221QS monitor that advertises 4k resolution. 

I have a linux desktop which is defaulting to 1080p resolution.

I am not able to set it to a 4k resolution either through the monitor. 

I read in the forums that I need to update the driver. I dont find any. 

How can I achieve 4k resolution with LINUX. Please help!

Thanks 

Guru