I have a Precision 5510 connected to a dock. I have two monitors connected to the dock:
Dell S2440L - Connected to DisplayPort
HP Pavillion 32 - Connected to HDMI
Both monitors are working fine, but the HP monitor should allow a resolution of 2560x1440 but only goes up to 1920x1080. This monitor does work at 2560x1440 on another computer so I know it does support that resolution.
I have updated all the drivers with no effect.
Update: If I connect the HP monitor directly to the laptop rather than through the dock, I am able to set it to 2560x1440, so it seems it's just the dock that is the problem. However, the documentation for the dock says that it should support this resolution