Provided by: libsvga1-dev_1.4.3-31_amd64 bug


       vga_getmodeinfo - returns pointer to mode information structure for a mode


       #include <vga.h>

       vga_modeinfo *vga_getmodeinfo(int mode );


       The function returns a pointer to a statical allocated mode information structure which is
       filled out with details for a video mode mode.

       #include <vga.h> defines vga_modeinfo as

       typedef struct {
            int width;
            int height;
            int bytesperpixel;
            int colors;
            int linewidth;
            int maxlogicalwidth;
            int startaddressrange;
            int maxpixels;
            int haveblit;
            int flags;
       /* Extended fields, not always available: */
            int chiptype;
            int memory;
            int linewidth_unit;
            char *linear_aperture;
            int aperture_size;
            void (*set_aperture_page) (int page);
            void *extensions;
       } vga_modeinfo;

       If the given mode is out of range, NULL is returned.  Beware, even when  vga_getmodeinfo()
       returns  details  about  a  certain mode, you must check if it is currently available (may
       depend on memory size and other details) with vga_hasmode (3).

       The fields meaning in detail:

   Basic mode details
       width  Width of mode in pixels.

       height Height of mode in pixel lines.

              Bytes per pixel. This is 1, 2, 3, or 4 (for 256, 32K & 64K, 16M, 16M$ modes) and  0
              for planar VGA modes.

              Logical scanline width in bytes. This is the memory offset between two pixels above
              each other in two adjacent screen lines. It is not valid to assume  that  linewidth
              == width * bytesperpixel in general!

       colors The number of colors which you can display simultaneously 2, 16, 256, 32768, 65536,
              or 16777216.  Generally 16 and 256 mean that a color lookup table is used. 2  means
              that only black/white is used and the others use some high/true color mode.

   Possible modifications of the memory layout
              The  maximum logical scanline width (in bytes) which you can set for this mode with
              vga_setlogicalwidth(3) while still expecting a perfect screen image.

              Mask  of  changeable  bits  of  start  address  (in  pixels).  All  bits  zero   in
              startaddressrange  must  also  be zero in a call to vga_setdisplaystart(3) when you
              want to avoid noisy video signals.

   Memory size
              Maximum number of pixels that will fit  in  a  logical  screen  (depends  on  video

   Further, advanced capabilities
              Indicates whether the following bitblit functions are available. It is a logical or
              of the following predefined values (which each have only one bit set).

                     has vga_bitblt(3) old style accelerator function.

                     has vga_fillblt(3) old style accelerator function.

                     has vga_imageblt(3) old style accelerator function.

                     has vga_hlinelistblt(3) old style accelerator function.

                     has vga_blitwait(3) old style accelerator function.

       flags  Miscellaneous flags.  It is a logical or of the following predefined values  (which
              each have only one bit set).

                     vga_setreadpage(3) and vga_setwritepage(3) are available in this mode.

                     Mode  is  interlaced, which means it will tend to flicker and the user might
                     be happier if the application chooses another mode.

                     Mode user mode X like memory  layout  (planar  256  colors  VGA  mode).  See
                     vga_setmodeX(3) for some explanations.

                     Dynamically  loaded  mode.  This mode was defined in /etc/vga/libvga.conf by
                     the user. He will probably prefer its usage. However, usually this should be
                     of no interest to the user.

                     Mode can be set to linear addressing with vga_setlinearaddressing(3).

                     Linear addressing is already enabled for this mode.

                     The  extended  fields  in  this  information  structure  are set to sensible
                     information. If EXT_INFO_AVAILABLE is not set you  should  even  not  access
                     these fields as you might have encountered an old version of svgalib and the
                     fields migth actually not have been allocated at all.

                     For 16M4 modes it means that the 4 bytes per pixel actually mean 0BGR rather
                     than  BGR0  as  per default. For 16M mode it means that the 3 bytes actually
                     mean RGB instead of BGR.

                     The first is a general limitation of Mach32, the latter one of Mach32 with a
                     ramdac of type 4. The vga_ drawing functions takes this into account.

                     A vga_ext_set(3) is available and can be called.

   Extended mode information
       You must check for EXT_INFO_AVAILABLE in flags before trying to access these values.

              the  chiptype  that  was  detected/set.  This  specifies  a  subtype of the current
              vga_getchipset(3) setting whose value depends on the chipset.  It  should  be  only
              used for debugging or internally.

       memory memory available on the SVGA card in KB.

              use only a multiple of this value for set_logicalwidth(3) or set_displaystart(3) to
              ensure graceful alignment of lines onto  the  vga  memory  in  this  mode  and  for
              noiseless video signals.

              ptr  to  a  mmaped  secondary  linear  framebuffer  (not  related  to  the  use  of
              vga_setlinearaddressing(3)) (NULL if unavailable)

              size of the secondary framebuffer in KB. 0 if unavailable.

              a function taking an int as parameter to select a page in the framebuffer addressed
              by read/writes to this memory arey (if aperture_size < memory.

              pointer  to additional, internal, chipset specific info (contents of the EEPROM for
              Mach32 driver.)

       The vgatest(6) demo displays most of this info for all supported modes.


       svgalib(7),   vgagl(7),   libvga.config(5),   vgatest(6),   vga_hasmode(3),   vga_init(3),
       vga_setmode(3),   vga_getcurrentmode(3),   vga_getdefaultmode(3),   vga_lastmodenumber(3),
       vga_getmodename(3),    vga_getmodenumber(3),    vga_setlogicalwidth(3),     vga_bitblt(3),
       vga_fillblt(3),  vga_imageblt(3),  vga_hlinelistblt(3),  vga_blitwait(3), vga_setmodeX(3),
       vga_getchipset(3), vga_ext_set(3), vga_setlinearaddressing(3)


       This manual page was edited by Michael Weller  <>.  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

       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