From: Marcus Sundberg <mackan@stacken.kth.se>
  To  : ggi-develop@eskimo.com
  Date: Fri, 11 Sep 1998 05:30:08 +0200

Re: SYNC mode should go

mentalg@geocities.com wrote:
> 
> On Thu, 10 Sep 1998, Marcus Sundberg wrote:
> 
> > Actually we should REALLY go all the way and introduce framebuffer
> > lock/unlock calls into libggi.
> 
> That's (in part) what I've been toying with implementing, although I'm
> afraid I fried my brain trying to figure out how to work around mansync :)
> Exactly what API did you have in mind for that?

ggiLock(vis) before you can access the framebuffer(s) directly,
and ggiUnlock(vis) when you're done.
Using drawing functions (which might be accelerated while the screen
is locked will cause undefined behaviour, as will accessing the
frambuffer when it's unlocked.
The screen is not guaranteed to be updated until you call ggiUnlock()

For apps that only access the framebuffer ggiUnlock(vis);ggiLock(vis);
will have the same effect as ggiFlush(vis); currently does. Apps that
mixes accel/direct access will call the functions as apropriate.
Apps that don't hit the DirectBuffer at all should call ggiFlush()
to flush the accel queue, but they could call ggiLock();ggiUnlock()
to get the same effect.

//Marcus
-- 
-------------------------------+------------------------------------
        Marcus Sundberg        | http://www.stacken.kth.se/~mackan
 Royal Institute of Technology |       Phone: +46 707 295404
       Stockholm, Sweden       |   E-Mail: mackan@stacken.kth.se