Subject: Re: Frame buffer / mmap() weirdness
From: Michael Schmitz (schmitz@mail.biophys.uni-duesseldorf.de)
Date: Wed Dec 01 1999 - 04:12:09 MST
> > > 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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