Frame buffer / mmap() weirdness

[Michael Schmitz]

> > > I think it will make munmap() more difficult to implement. Furthermore I see no
> > > provisions for this in the current mmap() code. And it will break backwards
> > > compatibility.
> > 
> > Don't know for mmap(), but it seems the only change to munmap() is
> > to clear the appropriate number of low-order bits in its first argument
> > ( addr & 0xfffff000 for 32-bit machines with 4k page size).
> 
> You are right. Since I guess the other mmap()s in the kernel are POSIX
> compliant, I feel silly now.

It will still break backwards compatibility (i.e. old X servers). We can
catch the case of old kernels used with new X servers but not the other
way. 

Either way - I recall getting errors from the generic mmap code when
passing not page aligned addresses back from fb_mmap. Has something
changed in the mmap code to remove this restriction? 

	Michael

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