[Oberon] VESA code removed in Bluebottle?

Paul Reed paulreed at paddedcell.com
Tue Apr 6 15:13:25 CEST 2004

> Date: Fri, 2 Apr 2004 16:42:56 +0200
> From: Stefan Salewski <Salewski at PHYSnet.Uni-Hamburg.de>

> Yes, screen-resolution up to 1280x1024 can be selected in a simple way 
> using code-numbers. I think this was the way before VESA 3.0, and it 
> gives default refresh rates, which is only 60 Hz for my Matrox G450. 
> Vesa 3.0 allows even higher screen resolution and arbitrary refresh 
> rate, but programming this is much more complicated. In the 
> VESA-Manual strange terms like "FAR-POINTER", NEAR-POUNTER", "REAL 
> MODE", "PROTECTED MODE" occur. So extending VESA-Code is not a simple 
> task. But there was module DisplayLinear.mod in last release of 
> Native-Oberon with much VESA-3.0-Code (if I remember correctly). 
> Maybe we can port this to BlueBotttle.
> If I should decide to go on playing with Bluebottle, then I have to do 
> something against the 60 Hz flicker of my CRT.
> The fastest and simplest solution is to use a 1280x1024 TFT.  We have 
> a few here in the institute, maybe I can exange my CRT. 
> Having a working VESA-3.0-Display-Driver seems to be very important 
> for BlueBottle, but I am not sure if I will be able to do it. Not too 
> much time, not much knowledge about dirty low level 80x86 
> hardware-programming, and no one like Pieter Muller behind me.


I can probably help with your hardware programming and VESA issues 
(I've implemented a banked VESA 1.x driver for my own version of the 
Oberon system) but I have a couple of comments before we start:

1. I've actually had the OPPOSITE problem with Linux (Knoppix) and my
TFT, which only does 60Hz vsync.  The default refresh rate for
my video card in 1280x1024 seems to be 85Hz (it's an SiS chip), and my
TFT goes blank, saying out of range.  Aaargh!

2. Are you saying that the Native DisplayLinear.Mod works correctly on
your system?

3. (Not for Stefan!)  Why was the display driver changed anyway?  Pieter
seemed to keep the drivers in step between Aos and Native, for exactly 
this kind of reason, I presume. :)

Paul Reed

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