1vga_setlinearaddressing(3)    Svgalib User Manual   vga_setlinearaddressing(3)
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NAME

6       vga_setlinearaddressing - switch to linear addressing mode
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SYNOPSIS

9       #include <vga.h>
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11       int vga_setlinearaddressing(void);
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DESCRIPTION

15       Switch  to  linear addressing mode. This maps all (or most) of the SVGA
16       memory at the position returned by vga_getgraphmem(3) (which will prob‐
17       ably   change   by   the   call   to  vga_setlinearaddressing()).   The
18       vga_set*page(3) calls are no longer required. This ensures optimal per‐
19       formance, however, not all cards support it (and not in all modes).
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21       Use  vga_modeinfo(3)  to  check  for  availability of the function in a
22       given mode.
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24       Furthermore, some cards (Cirrus) just enable this  buffer  at  a  fixed
25       hardware  address.  For Cirrus it is mapped at 14MB so you should never
26       used it if you have more than 14MB of memory (But how does an  applica‐
27       tion  know?).   The  Mach32  support for this is smarter. It makes this
28       feature only available when it is safe to be used.
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30       To avoid all this problems you can use
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33       nolinear
34              Inhibit use of a linear mmaped frame buffer.
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36       linear Allow (not enforce!) use of a linear mmaped frame buffer.
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38       in the /etc/vga/libvga.config file to disable the linear  frame  buffer
39       if it cannot be used.
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41       Returns  the  size of the mapped framebuffer if successful (can be less
42       than total video memory), -1 if not.
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44       The testlinear(6) demo shows the use of this feature (and if  it  works
45       for you).
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SEE ALSO

48       svgalib(7), vgagl(7), libvga.config(5), testlinear(6), vga_modeinfo(3),
49       vga_getgraphmem(3),         vga_setpage(3),         vga_setreadpage(3),
50       vga_setwritepage(3), vga_setlinearaddressing(3)
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AUTHOR

54       This  manual  page  was  edited by Michael Weller <eowmob@exp-math.uni-
55       essen.de>. The exact source of the referenced function as  well  as  of
56       the original documentation is unknown.
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58       It is very likely that both are at least to some extent are due to Harm
59       Hanemaayer <H.Hanemaayer@inter.nl.net>.
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61       Occasionally this might be wrong. I hereby asked to be excused  by  the
62       original author and will happily accept any additions or corrections to
63       this first version of the svgalib manual.
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67Svgalib (>= 1.2.11)              27 July 1997       vga_setlinearaddressing(3)
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