MGA EXA: problems when writing to A8 textures/pictures

[Ville Syrjälä]

On Thu, Sep 14, 2006 at 07:35:55PM +0200, Tilman Sauerbeck wrote:
> Ville Syrjälä [2006-09-14 20:06]:
> > On Thu, Sep 14, 2006 at 06:31:00PM +0200, Tilman Sauerbeck wrote:
> > > Hi,
> > > I'm almost finished with the EXA implementation in the MGA driver, but
> > > I've got one major problem left.
> > > 
> > > Rendering to A8 textures is broken in weird ways. It's easily
> > > reproducable with rendercheck doing Src blends (you'll need to get
> > > rendercheck from git to see the errors though).
> > 
> > I had a quick look at the code.
> > 
> > Did you enable bypass332 and nodither bits in MACCESS? I didn't see it.
> 
> I think I didn't try the combination of these two flags recently.
> Using both for A8->A8 writes fixes these rendering issues :)
> 
> It also adds more artefacts to A8 Add blends though, but these can
> probably be fixed by adjusting DUALSTAGE0...

IIRC TW8A actually behaves like I8, ie. every channel has the same 
value.

I also noticed (with glean) that srcblendf and dstblendf (ALPHACTRL) 
don't seem to work correctly when ADD is selected in the TDUALSTAGE 
registers.

-- 
Ville Syrjälä
syrjala at sci.fi
http://www.sci.fi/~syrjala/