Re: Advice sought on approach.

On 5 Mar 2003, Alex Bennee wrote:

On Wed, 2003-03-05 at 13:26, Antonino Daplas wrote:

quoted

On Wed, 2003-03-05 at 20:37, Alex Bennee wrote:

quoted

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 -- geert@linux-m68k.org

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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