On Mon, Dec 06, 2004 at 09:16:19 -0500, Michael wrote:

> > We already have MI code to do most of that - vga_subr.c rev 1.14
> 
> So vga can work without a PCish BIOS these days?  Hmm, a cursory
> glance at the code seems to indicate that it expects the legacy
> registers ( 0x3b0 and up ) active - is there anything to put a VGA
> into legacy mode? OF on a Mac certainly doesn't do that, usually it
> doesn't even enable IO access at all and sticks to the memory mapped
> registers.

I'm admittedly, not very clued in vga programming, but if the card
provides memory mapped i/o access it should be possible, I think, to
just map the registers via memory space and pass that as a bus space
handle.  Doing this for netwinder is on my todo list, so that plain
text mode vga(4) can be used instead of igsfb(4).  (I don't think vga
in netwinder is even accessible via i/o space, but nettrom (firmware)
and linux use it text mode).

But I'm not sure how well would it work for macppc, where different
models have different cards.  Still may be a handy option for the
models that can do it.


SY, Uwe
-- 
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