I am one of the OpenChrome project maintainer and pretty much the sole developer (at this point in time).
OpenChrome is an X Server DDX for VIA Technologies IGPs.
I had a report over at bugs.freedesktop.org that a user reported that OpenChrome was not working if Linux 4.5 kernel or later was used, but was okay if Linux 4.4 kernel was used.
It appears that vesafb (VESA frame buffer device driver) is claiming the VIA Technologies IGP frame buffer region, and as a result, when X Server tries to load OpenChrome, OpenChrome will fail to allocate the frame buffer, and the X Server will not start.
The user who reported this bug told me that if he did not allow the loading of vesafb, the X Server will boot fine.
The original bug reporter noticed this with Arch Linux, and another person also observed the same bug with Fedora 23.
OpenChrome itself had issues with error handling when the frame buffer was not allocated, and those issues were fixed with OpenChrome Version 0.4.186 or later.
I hope to get a response soon, and hope that this bug is fixed with Linux 4.5, 4.6, and 4.7.
Please note that I choose this bug to be "blocking" since we plan to release a new version of OpenChrome soon, and this bug will ensure that all VIA IGPs to fail if Linux 4.5 or later is used.
It is an urgent problem to fix for VIA IGP users.