Re: [Linux-fbdev-devel] fb_info ``disp'' field and multiple fb's

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

On 15 Feb 2002, Emmanuel Michon wrote:
> all fb implementations I find so far fill the disp
> field:
> 	fb_info.disp = &disp; /* used during initialization */
> with a 
> static struct display disp;
> 
> and enable only one framebuffer device.

E.g. atyfb doesn't use a static struct display, but

    disp = &info->disp

> I'm writing code that allows one fb per pci device; and I
> have to support multiple ones. Should I extend fb_info like this:
> 
> struct moreinfo {
> struct fb_info fb;
> static struct display disp;
> struct pci_dev *pdev;
> };
> 
> static int vfb_getcolreg(u_int regno, u_int *red, u_int *green, u_int *blue,
>                          u_int *transp, struct fb_info *info)
> { 
> 	struct moreinfo *my=(struct moreinfo *)info;
>         ...
> }
> 
> and set during init:
> my->fb.disp=&my->disp;

Exactly.

> or is it enough to have one real struct display for all of them?

No, each head needs its own struct display.

> Seems disp has a dispsw member that has to change on a per fb basis.

Yes, since dispsw depends on the video mode. If you support multiple devices,
they can be in different video modes.

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