On Tue, Mar 17, 2015 at 11:54:31AM -0400, Kevin O'Connor wrote:
If the last mode set (while not in vm86 mode) was done from a VBE mode set call then disable the extra stack. This works under the premise that only a modern OS would invoke the VBE mode changing facilities and a modern OS would always call the vgabios with sufficient stack space.
This is an ugly hack to work around a problem Windows Vista (and possibly later Windows releases) has with the VGA BIOS using a stack in the e-segment.
FYI, I pushed (a slightly modified version of) this patch to the master repo.