[solved] Elitebook 820 G2 with docking station: screen resolution not correct

[Conn]

Hi,
I'm running Mojave 10.14.1 on my EliteBook 820 G2. I have a problem with the screen resolution when I connect the Notebook via docking station (HP 2013 ultra slim docking station with newest available firmware). On the 4k 27" Monitor the maximum I get is 1920x1200 - but not the 2560x1440.
Where can I set the correct resolution?
Thanks in advance!

 

[RehabMan]

Hi,
I'm running Mojave 10.14.1 on my EliteBook 820 G2. I have a problem with the screen resolution when I connect the Notebook via docking station (HP 2013 ultra slim docking station with newest available firmware). On the 4k 27" Monitor the maximum I get is 1920x1200 - but not the 2560x1440.
Where can I set the correct resolution?
Thanks in advance!

What kind of port/cable are you using (HDMI or DP)?
Is the result different when you use the DP port directly on the laptop?

 

[Conn]

I use DP and yes- it is the same result as by using the docking station.

 

[RehabMan]

I use DP and yes- it is the same result as by using the docking station.

What do you see in SysPrefs->Displays?
What if you hold Option while clicking "Scaled"?
You should try adding kernel flag -cdfon.

 

[Conn]

Thank you- I will give it a try! Unfortunatelly now I‘m on business trip until friday next week.

 

[Conn]

Hey RehabMan,
your solution with the -cdfon bootflag did the trick! Now the external monitor is working with 4k 2560x1440 resolution. Many thanks!

 

[RehabMan]

Hey RehabMan,
your solution with the -cdfon bootflag did the trick! Now the external monitor is working with 4k 2560x1440 resolution. Many thanks!

Marked solved.