Subject: Re: Adding video mode info to struct wsscreen_descr
To: Matthias Drochner <M.Drochner@fz-juelich.de>
From: Bang Jun-Young <junyoung@mogua.com>
List: tech-kern
Date: 07/10/2002 21:25:57
On Wed, Jul 10, 2002 at 01:59:21PM +0200, Matthias Drochner wrote:
> 
> > It would make sense with i386, but not with others.
> 
> Right.
> Except you are going to emulate...
> 
> > Even on i386, VESA BIOS provides limited number of video
> > modes, so display drivers have to know how to do mode switching. 
> 
> For mode switching, in general extended registers are needed.
> So there are 2 possibilities:
> a) you know the card, then the driver can do it
> b) you don't, then the BIOS has to do it
> 
> Mixing a and b is dangerous at least.

Sure, but when you don't know video card details, you can't take
maximum ability like hardware acceleration from it. Generic framebuffer
driver is painfully slow in most cases, as you will be able to see that
with my current (unaccelerated) mach64 driver. Maybe you'll feel like
using Apple II.

> 
> btw, on my (not really fancy) grahics card, the VESA BIOS
> knows about 44 modes.

But that's all. VESA abandoned updating their BIOS years ago, so don't
expect it to have support for 1600x1200 at 85 Hz, non-interlaced.

Jun-Young

-- 
Bang Jun-Young <junyoung@mogua.com>