Thought some people here might be interested in this too...  Description
quoted below.
-- 
Jeff Garzik             | "Mind if I drive?"  -Sam
Building 1024           | "Not if you don't mind me clawing at the
MandrakeSoft            |  dash and screaming like a cheerleader."
                        |      -Max


> This patch, against 2.4.0-test10-pre6, updates bttv to use the new and
> groovy method of supporting mmap.
> 
> Advantages:
> * Code more simple.
> * mmap now only limited to number of free pages in the system (busts vmalloc limits)
> * mmap no longer requires vmalloc, or remap_page_range.
> 
> Disadvantages:
> * Requires videodev API update (new member: mmap_vma).
> * KNOWN BUG: If your gbufsize causes a frame to cross a page boundary,
> you lose.  The code doesn't support this, and doesn't check for it
> either.  Boom.  (this is fixable though)
> * Totally untested.  I don't own any bttv hardware.
>