Re: [Linux-fbdev-devel] [PATCH] fix endian problem in color_imageblit

[Geert Uytterhoeven]

On Sat, 21 Dec 2002, Russell King wrote:
> On Sat, Dec 21, 2002 at 11:45:44AM +0800, Antonino Daplas wrote:
> > The pseudopalette will only matter for truecolor and directcolor as the
> > rest of the visuals bypasses the pseudopalette.  Typecasting to
> > "unsigned long" rather than "u32" is also safer (even for bpp16) since
> > in 64-bit machines, the drawing functions use fb_writeq instead of
> > fb_writel.
> 
> Erm, what does the size of the drawing functions have to do with the
> size of the pseudo palette.  The pseudo palette is only there to encode
> the pixel values for the 16 console colours.

Indeed.

> This means that a 64-bit pseudo palette would only be useful if you have
> a graphics card that supports > 32bpp, otherwise a 32-bit pseudo palette
> is perfectly adequate, even if you are using fb_writeq.

Yep. Cards with bpp > 32 are rumoured to exist, but there is no fbdev support
for them right now.

> (note that fbcon doesn't support > 32bpp, so we will only ever look at
> the first 32 bits, and having it be 64-bit would just be a needless
> waste of space imho.)

And this can be fixed, once we have some fbdev driver that uses bpp > 32.

Note that the size of the entries in the pseudo palette used to depend on the
mode, i.e. u16 for bpp = 16, u32 for bpp = 24 or 32.

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [e-mail]

In personal conversations with technical people, I call myself a hacker. But
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							    -- Linus Torvalds