Man

Command Section
vga_setlinearaddressing(3)    Svgalib User Manual   vga_setlinearaddressing(3)

NAME
       vga_setlinearaddressing - switch to linear addressing mode

SYNOPSIS
       #include <vga.h>

       int vga_setlinearaddressing(void);

DESCRIPTION
       Switch to linear addressing mode. This maps all (or most) of the SVGA
       memory at the position returned by vga_getgraphmem(3) (which will
       probably change by the call to vga_setlinearaddressing()).  The
       vga_set*page(3) calls are no longer required. This ensures optimal
       performance, however the drawing functions of svgalib do not support
       this memory layout and not all cards support it (and not in all modes).

       Use vga_modeinfo(3) to check for availability of the function in a
       given mode.

       Furthermore, some cards (Cirrus) just enable this buffer at a fixed
       hardware address.  For Cirrus it is mapped at 14MB so you should never
       used it if you have more than 14MB of memory (But how does an
       application know?).  The Mach32 support for this is smarter. It makes
       this feature only available when it is safe to be used.

       To avoid all this problems you can use

       nolinear
              Inhibit use of a linear mmaped frame buffer.

       linear Allow (not enforce!) use of a linear mmaped frame buffer.

       in the /etc/vga/libvga.config file to disable the linear frame buffer
       if it cannot be used.

       Returns the size of the mapped framebuffer if successful (can be less
       than total video memory), -1 if not.

       The testlinear(6) demo shows the use of this feature (and if it works
       for you).

SEE ALSO
       svgalib(7), vgagl(7), libvga.config(5), testlinear(6), vga_modeinfo(3),
       vga_getgraphmem(3), vga_setpage(3), vga_setreadpage(3),
       vga_setwritepage(3), vga_setlinearaddressing(3)

AUTHOR
       This manual page was edited by Michael Weller <[email protected]
       essen.de>. The exact source of the referenced function as well as of
       the original documentation is unknown.

       It is very likely that both are at least to some extent are due to Harm
       Hanemaayer <[email protected]>.

       Occasionally this might be wrong. I hereby asked to be excused by the
       original author and will happily accept any additions or corrections to
       this first version of the svgalib manual.

Svgalib (>= 1.2.11)              27 July 1997       vga_setlinearaddressing(3)
Command Section