The setup of these Chromebook hosts is not standard: the BIOS has been flashed from MrChromebox supplied UEFI BIOSes.
fi-skl-caroline Samsung Chromebook XE510
fi-kbl-soraka HP ChromeBook X2
This appears to be a duplicate of bug 107859. As Arek mentions on that bug, it appears to be a system configuration / firmware issue rather than anything we can directly influence on the driver side.
*** This bug has been marked as a duplicate of bug 107859 ***