Re: PATCH: bugfix fü r RadeonFB(against 2.4.22-ac4, bug in 2.6.0-test9, too)

[Geert Uytterhoeven]

On Wed, 5 Nov 2003, Ronald Lembcke wrote:
> The following patches make a few framebuffer-drivers behave (imho) more
> sensible: (Matrox and Riva allready behave like this)
> 
> When selecting a video mode with bits_per_pixel == 16 is selected, but
> green.length != 6 (... 0 because the calling programm made no assumtion
> if the mode is 5/6/5 or maybe 6/5/5 or whatever) a 15 bpp mode is
> selected with 5/5/5. 
> That's not nice ... when 16 bpp were requested.

Your change is not correct: bpp is the _physical_ bits per pixel, i.e. it's 16
for both color depth 15 (5/5/5 mode) and color depth 16 (5/6/5).

To differentiate between 5/5/5 and 5/6/5, you have to look at green.length, and
apply standard fbdev fit-our-round-up[*] rules.

Note that some hardware in addition does RGBA4444, too.

Gr{oetje,eeting}s,

						Geert

[*] If a value doesn't fit, try to round it _up_. If that fails, return an
    error.
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

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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