From: Andreas Beck <becka@rz.uni-duesseldorf.de>
  To  : ggi-develop@eskimo.com
  Date: Fri, 13 Aug 1999 01:28:51 +0200

Re: GGI and XFree86 and stuff

> >         Actually I have permission to release binaries now, but I haven't
> > run across anyone besides myself who uses KGI and has a Savage4.  Also
> > the 3D accel performance is atrocious right now - since ping-pong buffers
> 
> Why not simply allocate one or two DMA buffers and go with a simple
> scheme until PP bufs arrive.  You can use the G200-GLX technique of
> reserving memory on bootup specifically for KGIcon, for example
> 'mem=120M' if you have 128MB of RAM.  Then you have a guaranteed 8MB for
> KGIcon to play with.  Anything should be faster than ioctl...

Before we get overly enthusiastic about PingPong and stuff:

The locking problem needs to be solved. If we go for an asynchronous
acceleration subsystem, we have to properly lock access to the framebuffer.
Not only on the application side, but as well in the linear-* libs.

To my knowledge Marcus has implemented that for the Matrox fbdev driver.
We should have a look at that and make it generic.

> >         VESA DDC.  I have specs as part of the Savage4 docs, but I don't
> > recall if they are otherwise publically accessible.
> AFAIK they are not.

Last time I looked, VESA still wanted money for them.

> Is DDC possible w/out BIOS?  

Sure. Anything is possible without BIOS. What's special about it ?
It's a program in a ROM ...

DDC is basically a (crappy) serial protocol on a monitor line that will give
you some info on the monitor.

> For example, will DDC code work on Alpha, PPC, etc.? 

Sure. You have to twiddle some card regs in somw way and watch them.

> And is there generic DDC in GGI? 

The exact method of reading the line is card-specific, but the rest would be
trivial to add.

Due to timing issues, I'd use a userland priviledged process to read that
stuff out. setmon would be suitable.

CU, ANdy

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