Mac64 - wrong colors and other problems

[Riccardo Mottola <riccardo.mottola@libero.it>]

Hi,

I am still trying to get a "useful" X11 on my iBook, that is, something 
where programs do not rash and display decent colors. WE know tat with 
the current driver all cairo-related apps will crash, so let's limit to 
others right now. I am investigating windowmaker + xterm and GNUstep 
apps (self compiled).

I have X running in 16 bit mode. By searching around, this would be the 
recommended way to have DRI working? Can somebody confirm that? I'd love 
to try also 24 bit.

IN the default mode (no xorg file) I get this in dpyinfo:
  number of visuals:    33
  default visual id:  0x21
  visual:
    visual id:    0x21
    class:    TrueColor
    depth:    16 planes
    available colormap entries:    64 per subfield
    red, green, blue masks:    0xf800, 0x7e0, 0x1f
    significant bits in color specification:    8 bits

Yes. 16bits :)

The stupid thing is that I think this mode is poorly supported.

If you launch the windowmaker preferences utility, you get totally funny 
colors, green text and pink icons!

Analyzing what GNUstep does is that the backend fails to properly use 
the 16bit draw mechanism, since it detects a depth of 32. Also, GNUstep 
is fast in drawing on 15-bit, 24 or 32bit dplsays, not 16bit where it 
falls back in a worse mode (right now not detected, but I saw the 
comments in the code).

Last but not least, if 16bit should five me DRI, I find this in the 
Xorg.log:

[ 13355.425] (II) MACH64(0): I2C bus "Mach64" initialized.
[ 13355.433] (II) MACH64(0): [drm] SAREA 2200+1208: 3408
[ 13355.434] drmOpenDevice: node name is /dev/dri/card0
[ 13355.449] drmOpenDevice: node name is /dev/dri/card0
[ 13355.471] [drm] failed to load kernel module "mach64"
[ 13355.472] (EE) [drm] drmOpen failed.
[ 13355.472] (EE) MACH64(0): [dri] DRIScreenInit Failed
[ 13355.473] (II) MACH64(0): EXA memory management initialized
         base     :  0xb764e000

Wow! Am I missing a module? I checked in
/lib/modules/3.12-1-powerpc/kernel/drivers/video/

and indeed I see nothing like mch64
So what is the best way out?

I tried focing 15bpp instead of 16, but I see no improvement of any sort.

I forced 24bit and voilà, things display! Albeit slowly.

Why is the default 16bit? I suppose DRI? and why does DRI not work?

Riccardo