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From: Matan Ziv-Av (matan@arava.co.il)
Date: Tue 22 Dec 1998 - 22:47:14 IST


Hi,

I'm trying to change svgalib, so that /dev/mem can be closed at the
same time that root privileges are given up.
The way I did it (that requires changing the drivers) is mmapping the
64k buffer at a0000 and the linear frame buffer in vga_init, and then,
wherever there was an mmap of /dev/mem, I substituted one of the
pointers.

This works great for banked memory access (zgv, quake2).
The problem is that testlinear fails with a SegFault. I tried a
simpler program that uses linear, and found out that if I use the
exact mmap in my program, It worked, i.e.
vbuf=mmap(...); works, while
vbuf=LINEAR_POINTER; fails. 

If anyone can tell me the reason, or has another idea for closing
/dev/mem at initialization time, I'd like to hear it.


If anyone has any wishes for the next version of svgalib, please
announce them here, so that I (and others on the list) might implement
them.


Matan Ziv-Av.        zivav@cs.bgu.ac.il


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