From: Morten Rolland <Morten.Rolland@asker.mail.telia.com>
  To  : ggi-develop@eskimo.com
  Date: Mon, 16 Aug 1999 17:46:12 +0000

Re: Ping-pong buffers on KGIcon are here!

Brian S. Julin wrote:
> 
> On Mon, 16 Aug 1999, Morten Rolland wrote:
> > This method could be made to work very well for applications using
> > either accels *xor* writing directly to the framebuffer, but how
> > about an application that (accidentially) mixes the two rather
> > closely?
> 
> That would qualify as a broken application.

You mean the app is broken if it doesn't flush accels (manually)
before painting the framebuffer?  I hope it is not illegal to
use a DirectBuffer along with GGI-primitives...

> Unmapping the framebuffer is for broken hardware.  If the locking
> isn't enforced by the kernel, a malicious application can hang the
> system.  If the hardware is not broken there's no reason to unmap
> the framebuffer, and the advisory lock method is fine.

Excellent! This explains a great deal.  So if I have a well
designed card that can cope with framebuffer-writes when accels
are being performed, I don't have to worry about my graphics
application stress-testing my paging tables... but rather flushing
at the right time.  This is good news indeed.

Thanx for enlightening me! 

Regards,
Morten Rolland