I have a Dell p2715q 27" 4K monitor and a HP 23xi pavilion 23" 1080p monitor for my dual monitor setup. The Dell monitor is currently running at a resolution of 3840x2160 @ 60Hz, while the HP is running at 1920x1080 @ 60Hz. When I initially setup the monitors on my desktop computer, which is running Linux Mint 17.3 Cinnamon (version 2.8.6) 64-bit, the scaling on the Dell was still set at 1, so everything was really tiny in comparison to the HP, which was scaling everything appropriately since it is not a HiDPI monitor like the Dell. When I changed the scaling to 2, everything on the Dell looked great, but the HP now makes everything twice as large.
Is there a way to scale the HiDPI Dell monitor at 2x, while keeping the HP monitor at 1x to make everything on both screens scale properly?