Re: CVS commit: src

[cgd%netbsd.org@localhost (Chris G. Demetriou)]

Michael Graff <explorer%flame.org@localhost> writes:
> > On NetBSD/alpha, you actually mmap the frame buffer, and thus don't
> > need permissions to get at /dev/mem.
> 
> So, why can't the x86 port have a little vga device that exports video
> memory, too?

uh, "what memory does it export"?

For PCI VGA (or other vides cards) cards, this is easy.  For other VGA
cards it's not quite so easy.  Obviously, for each, you can export the
'standard' VGA I/O and memory addresses, but as for any additional
regions only PCI can tell you what's up.  For non-PCI VGA cards on
PCs, /dev/mem (or an equivalent) is indeed the only way to go.  (The
'aperture driver' is equivalent, and has the same potential security
implications that allowing mappings of /dev/mem outside of 'real'
memory does.)

Despite Jason's off-the-cuff comment, wscons _doesn't_ do anything
useful for VGA at all.

It should, but that's another issue.


cgd
-- 
Chris Demetriou - cgd%netbsd.org@localhost - 
http://www.netbsd.org/People/Pages/cgd.html
Disclaimer: Not speaking for NetBSD, just expressing my own opinion.