Re: [Linux-fbdev-devel] Advice sought on approach.

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

On 5 Mar 2003, Alex Bennee wrote:
> On Wed, 2003-03-05 at 13:26, Antonino Daplas wrote:
> > On Wed, 2003-03-05 at 20:37, Alex Bennee wrote:
> > > Having read the fb-dev docs on www.linux-fbdev.org I'm a little confused
> > > as to what actually puts data into the framebuffer. Most of the
> > > framebuffer drivers just seem to deal with resolution and colourmap
> > > settings. Is this a case of having to re-implement the fbcon drivers as
> > > well to get what I want?
> > The pixels placed to the framebuffer are all done in the fbcon-cfb*.c
> > modules (if you use the generic functions).  This is for standard
> > character drawing.  The logo is drawn indepently (fbcon_show_logo in
> > fbcon.c).  User applications write directly to the framebuffer via the
> > mmap() function.
> 
> I think I understand now. When the fb_set_disp function is called I fill
> in the display struction with the console display operations. I've got
> two choices now:
> 
> 1. Create a new fbcon_cfb16 file which notes the changed areas before
> calling the generic function.
> 
> 2. Patch the current fbcon_cfb16 (with a CONFIG option) to add the
> change tracking facility in a more generic way.
> 
> I guess the question is is it worth doing 2 as a potential upstream
> patch? Or is this sort of thing so specialised I should just keep it all
> packed in my own fb driver?
> 
> I guess I can't easily implement user access via mmap without uploading
> the entire screen, which I'm not intending to do anyway because all I
> really need is the console support - at least for now.

If all you need is console support, please take a look at
drivers/video/newport_con.c, for the SGI Indy.

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