Frame buffer / mmap() weirdness

[Michael Schmitz]

> > According to fbset, it's at:  0x8a008900
> > Furthermore, it makes most sense that mmap() should take care of page
> > alignment issues for me so that the address returned by mmap() always
> > points to the data at [lseek(h, 0, SEEK_SET)].  This is not technically
> > difficult to implement, right?
> 
> 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.

And returning a different address than the one the kernel actually used
for the mapping isn't tecnically correct either. 

The problem (if I understood your problem right) did occur for m68k Mac
framebuffers earlier, and we tried a few things (passing back the
address+offset, passing the offset into the first page in fb_info, ...) 
and finally agreed on the current implementation. The corresponding code
should be in the fbdev X server since sometime last year (I hope; Geert
should have gotten the patch or made his own version). 

	Michael


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