Hi Thomas,

On Thu, Apr 20, 2023 at 1:10 PM Thomas Zimmermann [off-list ref] wrote:

Am 20.04.23 um 12:04 schrieb Sui Jingfeng:

quoted

What will happen if the 'screen_size' is not page_size aligned and mmap
will mapping in the granularity of pages ?

You need to map at page granularity. If screen_size is not page-size
aligned, there's this trailing buffer that is accessible, but cannot be
displayed. But userspace has no direct way of knowing that, so let's
ignore that problem for now.

Userspace can know, if fb_fix_screeninfo.smem_{start,len} match
the actual offset and size.

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