Re: [Linux-fbdev-devel] mmap()ing of FB memory area

[James S. <jsi...@tr...>]

> No, this is too rigid.
> 
> what we need is a onboard memory manager, which will know if we make 
> reservation of memory, and don't allow another app to use that memory,
> but allow another app to use memory that is not overlapping.

Basically you described emulating window IDs. This is tricky but can be
done. The trick I have seen to emulate window IDs is to mmap a region of
the framebuffer to a process. Then those page tables belong to it. If
another process accesses it it segfaults. Of course this limits your
window sizes a bit. They have to be alignied on 4K page boundaries. 

> The DRI/drm folk may do something such, but my understanding is that the 
> ressource management used is just a joke, since in truth it is the X
> server who does all of this. I may be wrong though.

I haven't looked at SAREA in detail. I have to look over the DRI 2 specs
in detail. The white paper is pretty crappy.