In particular, Ubuntu developers are figuring out how to address HiDPI support for the Ubuntu Linux boot experience -- when dealing with GRUB2's boot-loader menu and the Plymouth boot splash screen. Additionally, developers are investigating HiDPI support for Linux virtual consoles.
Developers at this week's vUDS session will be working on a 2x version of the GRUB2 font for basic HiDPI support by just appearing twice as big, working on GRUB2 support for returning a display's physical dimensions, work out support for a scaling factor within Ubuntu's Plymouth theme, and support for a scaling factor within the console-setup font configuration.
HiDPI Ubuntu Linux users can find out more details from these session notes. While Unity 7 HiDPI is still being tuned ahead of Ubuntu 14.04 LTS and some of this work might be done, not all of the HiDPI improvements will likely be ready for the "Trusty Tahr" release next month. More details on the Ubuntu 14.04 LTS HiDPI experience can be found by my recent articles of using the ASUS Zenbook ultrabook with Intel Haswell processor, most recently with Unity 7 Is Now My Desktop, Wins Over Xfce On HiDPI.