RE: [Linux-fbdev-devel] fbdev API problems

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

On 22 Nov 2001, Matt Sottek wrote:
> >> Currently mmio and fb pointers are in a PUBLIC data structure, a data
> >> structure that is defined for everyone using the fb interfaces, both
> >> kernel side and user side. 
> 
> >That is so you can do things like use the physical memory address of
> >the framebuffer to display a image from a TV card into it.
> 
> No doubt, as you state, there are applications that would need the
> physical framebuffer address. The problem is that when you just leave
> a pointer laying around in a public data structure there is no way
> for a user application to know when the pointer is valid and when it
> is not. If a unsuspecting TV capture card tried to use my physical
> address without knowing that I only have 64k banks the whole system
> would come down hard.

If it's not safe to use the pointer, set it to NULL and set the size to 0 as
well.

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