> This is true for VESA 1 but a lot less true for VESA 2.0. The original
> VESA bios extensions are basically 16bit non-reentrant add ons to the original
> PC bios graphical support. The 2.0 ones have a 32bit interface which does
> sort of meet the needs but has a reputation for poor performance.
VBE2 has a protected mode interface but you have to call the non-protected
mode functions to find out what its entry points are. The protected mode
interface only has three functions, and none of them is a mode switch.
So basically what you have to do is query and switch modes at boot-up
time before switching to protected mode and then you get to run your
operating system in that fixed mode.
I've looked at some of the 32-bit functions that NeoMagic gives back and
they don't look too shabby. They are quite short and mostly consist of I/O.
Anyway, the above paragraph from XFree is not correct as it is possible
by running the BIOS in a VM86 jail, which is basically what my driver does.
imc
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