Re: [Linux-fbdev-devel] Supporting various depth

[Geert U. <ge...@li...>]

On Wed, 13 Jun 2001, Romain Dolbeau wrote:
> Geert Uytterhoeven wrote:
> > Yes, by looking at the fb_var_screeninfo.{red,green,blue}.length fields. 
> > 
> > Cfb16 is the memory organization: packed 16 bits per pixel. How a pixel looks
> > like internally doesn't matter. So both RGB555 and RGB565 use fbcon-cfb16.c.
> 
> How does the user tell the system what he wants, then ? Will fbset
> recognize both -depth 15 and -depth 16 and fill the fields properly ?

No, use the -rgba option to specify the bitfield lengths.

> Right now, pm3fb just disregard whatever is in the length fields
> and use RGB8888/RGB565/CI8 for 32/16/8bpp (shame on me). Is there any
> requirements on the userland/the kernel about what is acceptable ?
> One could require RGB10_10_10_2 or RG232 or RGB4444, what is
> the driver supposed to to in case it doesn't support the required
> mode : change to a similar mode, do nothing,... ?

Driver should round up values until they fit, or return an error.

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@li...

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