Messages in this thread | | | Date | Tue, 31 Mar 2009 09:18:09 +0200 | Subject | Re: [PATCH] fbdev: fix color component field length documentation | From | Geert Uytterhoeven <> |
| |
On Tue, Mar 31, 2009 at 00:00, Michal Januszewski <spock@gentoo.org> wrote: > The documentation about the meaning of the color component bitfield lengths > in pseudocolor modes is inconsistent. Fix it, so that it indicates the > correct interpretation everywhere, i.e. that the 1 << length is the number > of palette entries. > > Signed-off-by: Michal Januszewski <spock@gentoo.org> > Cc: Krzysztof Helt <krzysztof.h1@poczta.fm> > Cc: Ville Syrjälä <syrjala@sci.fi> > Cc: Geert Uytterhoeven <geert.uytterhoeven@gmail.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Except for this:
> --- a/include/linux/fb.h > +++ b/include/linux/fb.h > @@ -172,8 +172,11 @@ struct fb_fix_screeninfo { > /* Interpretation of offset for color fields: All offsets are from the right, > * inside a "pixel" value, which is exactly 'bits_per_pixel' wide (means: you > * can use the offset as right argument to <<). A pixel afterwards is a bit > - * stream and is written to video memory as that unmodified. This implies > - * big-endian byte order if bits_per_pixel is greater than 8. > + * stream and is written to video memory as that unmodified. > + * > + * For pseudocolor, offset is always 0 and length, which should be the same ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This is not correct. Offset can be non-zero, e.g. for a 8 bpp frame buffer with 64 palette entries, where the palette index is stored in the upper 6 bits of the 8-bit pixel value, offset would be 2, and length would be 6. Not that I've seen that (so far)...
> + * for all color components, indicates the number of available palette entries > + * (i.e. # of entries = 1 << length). > */ > struct fb_bitfield { > __u32 offset; /* beginning of bitfield */ >
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |