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

[Sven L. <lu...@dp...>]

On Wed, Jun 13, 2001 at 03:49:41PM +0200, Geert Uytterhoeven wrote:
> On Wed, 13 Jun 2001, Romain Dolbeau wrote:
> > Is there a way to distinguish 15 and 16 bpp in 16bits pixels in
> > the fbdev/fbcon layer ?
> 
> Yes, by looking at the fb_var_screeninfo.{red,green,blue}.length fields.
> 
> > pm3fb support RGB565 in 16bpp, and I was just asked for 15bpp
> > (RGB555 + 1 bit Alpha or whatever). Do I simply reuse CFB16
> > and support both internally, is there a requirement that
> > CFB16 is one or the other, ... ?
> 
> 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.

So i suppose saying fbset -depth 15 could be done to switch the fb to
RGBA5551 mode ? 

BTW, what is fbset -depth 24 supposed to do, especially if the chip only
support 8, 16, and 32 bpp ?

should only fbset -depth 32 be supported ?

Also, i am experiencing some (maybe hardware) bugs, and would like to reset
the graphic chip. Is there an existing way to do this kind of stuff via ioctl
ore such (sure i could do it by hand under root, but i don't think fbcon/fbdev
would be really happy with it).

Friendly,

Sven Luther