Re: [Linux-fbdev-devel] [PATCH 2.6.20 1/1] fbdev, mm: hecuba/E-Ink fbdev driver

Antonino A. Daplas
2007-02-21T23:41:03Z

On Wed, 2007-02-21 at 11:55 -0500, Jaya Kumar wrote:
> On 2/20/07, Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> > Don't you need a way to specify the maximum deferral time? E.g. a field in
> > fb_info.
> >
>
> You are right. I will need that. I could put that into struct
> fb_deferred_io. So drivers would setup like:
>

Is it also possible to let the drivers do the 'deferred_io'
themselves? Say, a driver that would flush the dirty pages on
every VBLANK interrupt.

> static struct fb_deferred_io hecubafb_defio = {
> .delay = HZ,
> .deferred_io = hecubafb_dpy_update,
> };
>
> where that would be:
> struct fb_deferred_io {
> unsigned long delay; /* delay between mkwrite and deferred handler */
> struct mutex lock; /* mutex that protects the page list */
> struct list_head pagelist; /* list of touched pages */
> struct delayed_work deferred_work;
> void (*deferred_io)(struct fb_info *info, struct list_head
> *pagelist); /* callback */
> };
>
> and the driver would do:
> ...
> info->fbdefio = hecubafb_defio;
> register_framebuffer...
>
> When the driver calls register_framebuffer and unregister_framebuffer,
> I can then do the init and destruction of the other members of that
> struct. Does this sound okay?

It would be better if separate registering functions are created for
this functionality (ie deferred_io_register/unregister).

Tony