[F]Framebuffer driver using SM501 hardware.

Geert Uytterhoeven geert at linux-m68k.org
Wed Aug 17 22:42:01 EST 2005

On Wed, 17 Aug 2005, Andrey Volkov wrote:
> Geert Uytterhoeven wrote:
> > On Wed, 17 Aug 2005, Andrey Volkov wrote:
> > 
> >>Todo:
> >>- 16 bpp colormap (needed reverse endian support in fbcon/fbmem)
> > 
> > 
> > Can you please elaborate? For 2.6, there should be no such problems (for 2.4,
> > there are).
> Sorry for inexactitude, problem (as usually :)) in next (for case of
> MPC5200 connected through PCI to SM501): PCI on PPC (and hence SM501) is
> a little endian, PPC - big endian.
> Currently (up to 2.6.13-rc6) frame buffer routines use
> __raw_writeXX for write to fb memory. Result - garbage with colors in
> RGB565/RGB888 modes (but pixels, meanwhile, are in place). If using
> write[lw] - colors are diplayed correctly, but all image pixels are
> shifted for (RGB565). This is not bug of frame buffer, this is lack of
> some define in .config which tell fb/device driver how palette must be
> generated (more precisely it is unknown when must be RGB565, but when
> must be BGR565).

Sorry, I cannot follow.

 1. If it's a palette issue, your setcolreg() routine doesn't fill in correctly
    the pseudo palette,
 2. If it's a RGB565 vs. BGR565 issue, you don't fill in correctly the offsets
    in the color bitfields in fb_var_screeninfo,
 3. If it's an endian issue, it's RRRRRGGGGGGBBBBB vs.GGBBBBBRRRRGGGG, right?
    And then there's no much we can do...



Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds

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