From: Andreas Beck <becka@rz.uni-duesseldorf.de>
  To  : ggi-develop@eskimo.com
  Date: Sun, 8 Aug 1999 12:28:56 +0200

Re: GL, X, accel and ggi

> If I am using plain console text mode, I have to use SVGATextMode
> to set a new text mode. Well, guess what? SVGATextMode only supports
> SVGA standards. That means that if my graphics card had clocks, I
> would be stuck to the first 4. 

No. Wrong. If you have a card that is well supported by SVGATextMode, it
will even program the clockchip to anything you want. However most cards 
have lower limits for the maximum dotclocks in textmode due to the higher
bandwidth and weirder RAM-access-pattern it induces.

> I'm trying to get 2.2 configured so that it comes out small enough
> to compile in the FBCon + Permedia KGI drivers, just so I can run
> that thing in a way that doesn't hurt my eyes.

Tell me if you have problems. I'm running that combination right now, and my
Monitor says: 72.6kHz/131Hz at 640x480. The other console runs 1280x1024x16
and is still at 86.7kHz/78Hz.

> p.s. Does anyone have timings for an X display that will give me
> 640 by 480 on the INSIDE of an X window, taking into account window
> boarders and a scroll bar, and a title bar, and menus, and the
> oversized icons at the bottom of the screen? My monitor does 117
> vertical, 64.8 horizontal; my graphics card has a 230 dot clock
> (yea, way overpowered for the monitor.) [Extra credit: 800 x 600
> on the inside]

This is no problem. You have a fully programmable clockchip ?

O.K. - the idea is:

1. Find out how much border you need.

2. linearly scale the values in the XFree mode lines as needed.

Say you want 800x600 and have a mode for it and need 960x660 to compensate
for the borders.

That gives a factor of 1.2 for x and 1.1 for y.

Now you just scale all x values by 1.2 and all y values by 1.1.

Note, that x values typically need to be multiples of 8, so round
accordingly.

Scale up the clock by the x scale factor. This should give you a mode that
has the same horizontal refresh as the smaller one you generated it from.

It has a smaller vertical refresh, though, as you have more lines. 

3. Readjust your monitor for the new mode or use xvidtune.

CU, Andy

-- 
= Andreas Beck                    |  Email :  <andreas.beck@ggi-project.org> =