77 lines
2.2 KiB
Groff
77 lines
2.2 KiB
Groff
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.TH vga_setlinearaddressing 3 "27 July 1997" "Svgalib (>= 1.2.11)" "Svgalib User Manual"
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.SH NAME
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vga_setlinearaddressing \- switch to linear addressing mode
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.SH SYNOPSIS
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.B "#include <vga.h>"
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.BI "int vga_setlinearaddressing(void);"
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.SH DESCRIPTION
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Switch to linear addressing mode. This maps all (or most) of the SVGA memory at the
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position returned by
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.BR vga_getgraphmem (3)
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(which will probably change by the call
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to
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.BR vga_setlinearaddressing()).
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The
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.BR vga_set*page (3)
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calls
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are no longer required. This ensures optimal performance, however,
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not all cards support it (and not in all modes).
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Use
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.BR vga_modeinfo (3)
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to check for availability of the function in a given mode.
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Furthermore, some cards (Cirrus) just enable this buffer at a fixed hardware address.
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For Cirrus it is mapped at 14MB so you should never used it if you have more than 14MB
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of memory (But how does an application know?).
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The Mach32 support for this is smarter. It makes this feature only available when it is safe
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to be used.
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To avoid all this problems you can use
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.TP
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.B nolinear
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Inhibit use of a linear mmaped frame buffer.
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.TP
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.B linear
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Allow (not enforce!) use of a linear mmaped frame buffer.
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.P
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in the
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.I /etc/vga/libvga.config
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file to disable the linear frame buffer if it cannot be used.
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Returns the size of the mapped framebuffer if successful (can
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be less than total video memory), -1 if not.
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The
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.BR testlinear (6)
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demo shows the use of this feature (and if it works for you).
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.SH SEE ALSO
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.BR svgalib (7),
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.BR vgagl (7),
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.BR libvga.config (5),
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.BR testlinear (6),
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.BR vga_modeinfo (3),
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.BR vga_getgraphmem (3),
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.BR vga_setpage (3),
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.BR vga_setreadpage (3),
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.BR vga_setwritepage (3),
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.BR vga_setlinearaddressing (3)
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.SH AUTHOR
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This manual page was edited by Michael Weller <eowmob@exp-math.uni-essen.de>. The
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exact source of the referenced function as well as of the original documentation is
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unknown.
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It is very likely that both are at least to some extent are due to
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Harm Hanemaayer <H.Hanemaayer@inter.nl.net>.
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Occasionally this might be wrong. I hereby
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asked to be excused by the original author and will happily accept any additions or corrections
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to this first version of the svgalib manual.
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