[PATCH] RFC: framebuffer: provide generic get_fb_unmapped_area

[Geert Uytterhoeven]

On Mon, Nov 18, 2013 at 7:59 PM, Uwe Kleine-König
<u.kleine-koenig at pengutronix.de> wrote:
>> > +unsigned long fb_get_unmapped_area(struct file *filp, unsigned long orig_addr,
>> > +               unsigned long len, unsigned long pgoff, unsigned long flags)
>> > +{
>> > +       struct fb_info * const info = filp->private_data;
>> > +       unsigned long screen_size = info->screen_size ?: info->fix.smem_len;
>>
>> Why restrict this to screen_size? Fbtest will map the whole frame buffer memory.
> For me screen_size is zero. The logic to determine the size is copied
> from fb_read.

fb_read() only allows reading the visible screen, not the full frame
buffer memory.
fb_mmap() does allow mapping the full frame buffer memory (and the optional
MMIO registers, but you can't easily do that the same way on nommu, as it's
a discontiguous mapping).
So please use PAGE_ALIGN(info->fix.smem_len) as the limit.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
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                                -- Linus Torvalds