[vlc-devel] [PATCH] v4l/v4l2: add mmap() fall back for nommu systems

Rémi Denis-Courmont rdenis at simphalempin.com
Fri Jan 9 15:26:38 CET 2009

On Fri, 9 Jan 2009 13:21:34 +0100, Antoine Cellerier <dionoea at videolan.org>
> On Fri, Jan 09, 2009, Mike Frysinger wrote:
>> On Linux no-mmu systems, getting a shared mapping often results in
>> failure. If the mmap() in v4l failed with MAP_SHARED, then fall back to
> I'm not really sure how MAP_PRIVATE works. According to the man page it
> creates a private copy on write mapping. Won't that mean that the
> original memory area doesn't get updated?

Yes. That's the whole point of MAP_PRIVATE - doing copy-on-write to not
share your modifications with others.

Rémi Denis-Courmont

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