Re: radeon, apertures & memory mapping

["Michel Dänzer" <michel@daenzer.net>]

On Tue, 2005-03-15 at 08:52 +1100, Benjamin Herrenschmidt wrote:
> On Mon, 2005-03-14 at 11:20 -0500, Michel Dänzer wrote:
> > On Mon, 2005-03-14 at 18:12 +1100, Benjamin Herrenschmidt wrote:
> > > On Sun, 2005-03-13 at 23:28 -0500, Michel Dänzer wrote:
> > > > On Sun, 2005-03-13 at 17:43 +1100, Benjamin Herrenschmidt wrote:
> > > > > 
> > > > > And finally, I want to blank the screen (using the accel engine) before
> > > > > setting the new mode, so that we come out "clean" of the mode setting
> > > > > (without ugly artifact), and I will probably clean both fb's (simpler).
> > > > 
> > > > That would break X with UseFBDev.
> > > 
> > > How so ?
> > 
> > X assumes that the framebuffer (as in video RAM) contents are preserved
> > on mode switches.
> 
> Which I consider bogus :) Oh well... does it do a lot of other crappy
> assumptions like that ? What if I just can't allocate it and decide to
> put it elsewhere in vram ? (unlikely with my current scheme but
> possible). X needs to be fixed.

Be that as it may, it remains a fact that such a change would break
existing installations...

I think that mode setting and memory allocation should be separated. X
will always reserve enough video RAM for the largest resolution it uses
for the screen contents.


-- 
Earthling Michel Dänzer      |     Debian (powerpc), X and DRI developer
Libre software enthusiast    |   http://svcs.affero.net/rm.php?r=daenzer