It's prolly matter of how often you need to call the VESA stuff.
AFAIK bioscall(9) switches whole computer to real-mode and blocks
interrupts, this may incur serious performance problems if used
often. The VM86 mode doesn't have such issues, the process runs
as a common process and doesn't block other activity on the computer.

Jaromir

Brian Clough wrote:
> Does anyone have an opinion on the usefulness and stability of the i386
> "Biosacall" routine, for accessing the VESA interrupt calls (int10 fn 4FXX)?
> 
> I need access to those VESA functions that don't have protected mode entry points,
> from within my video driver, in a non X-window environment.  Obviously I'm talking
> about an i386 install here.
> 
> I want to keep this as simple as possible, so I'd prefer to avoid the use of an
> x86emu style emulator.  I'm not sure I could implement such a thing in a kernel
> driver anyway.
> 
> If anyone has any experience dealing with bioscall, I'd like to hear about any
> problems you may have run into.
> 
> -- 
> Brian Clough
> OS Development Group, Norwood, MA
> x(82)5015
> mailto:brian_clough@phoenix.com
> 


-- 
Jaromir Dolecek <jdolecek@NetBSD.org>      http://www.ics.muni.cz/~dolecek/
NetBSD - just plain best OS! -=*=- Got spare MCA cards or docs? Hand me them!