From mboxrd@z Thu Jan  1 00:00:00 1970
To: 9fans@cse.psu.edu
Subject: Re: [9fans] What a poor VGA support !
From: forsyth@vitanuova.com
MIME-Version: 1.0
Content-Type: text/plain; charset="US-ASCII"
Content-Transfer-Encoding: 7bit
Message-Id: <20020613132533.569F51999B@mail.cse.psu.edu>
Date: Thu, 13 Jun 2002 14:16:15 +0100
Topicbox-Message-UUID: abd1ea1a-eaca-11e9-9e20-41e7f4b1d025

>>But , please, tell me, because I'm curious : Why is it so difficult, so
>>impossible to add some kind of minimum VGA support  ?

because the only bit that is standard at the VGA register level
doesn't give you much, if you'd like some colour
(even 640x480x8 uses non-standard extensions).

there is a VESA bios interface that could be used to provide a card-independent
way of implementing a flat map but even several years ago
many cards didn't implement the 32-bit interface, and it could
only be activated from real mode.  things might have changed.
roger peppe had a version of (native) Inferno that tried the
real mode call (it wasn't easy), with some card-specific code as well,
and that worked reasonably well.  we've made that code available.

there's an amusing essay somewhere by the person at Be who
had to write the card support.   it wasn't straightforward.
how did they manage?  they had money (at the time) to throw at it,
at least one person, a fair number of machines and lots of cards
as samples.