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       s3 - S3 video driver


       Section "Device"
         Identifier "devname"
         Driver "s3"
         [Option "optionname" ["optionvalue"]]


       The s3 driver supports PCI video cards based on the following S3 chips:

       Trio32      86C732

       Trio64      86C764

       Trio64V+    86C765

       Aurora64V+  86CM65

       Trio64UV+   86C767

       Trio64V2/DX 86C775

       Trio64V2/GX 86C785

       Vision964   86C964

       Vision968   86C968

       Also driver supports the following RAMDACs:

       IBM 524, IBM 524A, IBM 526, IBM 526DB

       TI ViewPoint 3025


       s3 is an Xorg driver for S3 based video cards. The driver provides full
       accelerated  support for the following colour depths: 8, 15, 16 and 24.
       The overlay video (Xv) is  supported  in  depths  16  and  24  for  the
       Trio64V+, Trio64UV+, Trio64V2/DX and Trio64V2/GX chips.


       Please  refer  to xorg.conf(5) for general configuration details.  This
       section only covers configuration details specific to this driver.  All
       options  names  are case and white space insensitive when parsed by the
       server, for example, "trio 32/64" and "Trio32/64" are equivalent.

   Chip overriding
       The driver auto-detects the  chipset  and  RAMDAC,  but  the  following
       Chipset  names  may  optionally  be specified in the configuration file
       "Device" section, and will override the auto-detection:

           "964-0", "964-1"  86C964 (rev.0 and rev.1)

           "968"             86C968

           "Trio32/64"       86C732/86C764

           "Aurora64V+"      86CM65

           "Trio64UV+"       86C767

           "Trio64V2/DX/GX"  86C775/86C785

       The 86C765 (Trio64V+) is Chipset "Trio32/64" with  ChipRev  greater  or
       equal 0x40.

       An overriding of RAMDAC auto-detection currently is not implemented.

   Colour depth
       For  every supported colour depth the X server automatically selects an
       appropriate number of bits per pixel (bpp) for framebuffer. The depth 8
       is  represented  by 8 bpp framebuffer (1 byte/pixel), the depths 15 and
       16 (respectively 5.5.5 and 5.6.5 pixel formats) are represented by  the
       16   bpp   framebuffer  (2  bytes/pixel).  Whenever  the  depth  24  is
       configured, the X server by default uses  the  32  bpp  framebuffer  (4
       bytes/pixel),  and  the hardware is adjusted accordingly to the X.8.8.8
       pixel format, where X is the ignored upper byte.

       As the second option for the depth 24, the X server can  be  configured
       to  use 24 bpp framebuffer with the 8.8.8 pixel format (3 bytes/pixel),
       which is supported by Trio64V+, Trio64UV+, Trio64V2/DX and Trio64V2/GX.
       If  the video board has limited video RAM the 24 bpp framebuffer has an
       advantage over 32 bpp framebuffer as it requires less memory  to  store
       screen,  and, therefore, more space will be available for a video frame
       (see "Overlay video" section).  The 24 bpp framebuffer can be  selected
       by  X server's option -fbbpp 24 or by specifying DefaultFbBpp option in

           Section "Screen"
             DefaultFbBpp 24
             DefaultDepth 24

       However, the 24 bpp framebuffer mode has the hardware limitations:  (i)
       the  2D  acceleration  doesn't  work with this mode (use the "shadowFB"
       option to speed  up  drawing  routines  in  this  case);  (ii)  24  bpp
       framebuffer  cannot  be  used  with  either  interlaced  or  doublescan
       graphics modes.

   Overlay video
       If your video board has limited RAM it would be useful to estimate  how
       large  video  frame  might be placed in offscreen video memory. Suppose
       that the video board has 2 MB of RAM, and X  server  is  configured  to
       display  800x600  with  the depth 24. By default the 32 bpp framebuffer
       will be chosen for this depth, so 800 x 600 x  4  =  1875  kB  will  be
       reserved  for  screen,  and 2 MB - 1875 kB = 173 kB will remain for the
       offscreen area. This is sufficient space, for example, for the VCD NTSC
       352x240 frame. If you need to upscale video with a bigger frame, but it
       doesn't fit the offscreen area, the only way to do  this  is  to  lower
       either  the  resolution  or  framebuffer's  depth  or  both  before the
       viewing, otherwise, you will get the allocation error and will not  see
       the video. For example, with 24 bpp framebuffer and the same resolution
       800x600 the offscreen area will be about 640 kB - it's enough  for  the
       640x480  frame. 800x600 with the 16 bpp framebuffer gives about 1110 kB
       of offscreen area - this allows to upscale up to 768x576 movies.  Note,
       that  all  movie  resolutions  in  examples  above  are  provided  as a
       reference; the movies can have the different  aspect  ratios  and  non-
       standard dimensions. A total pixel amount is the main consideration not
       the certain width and height.

       Due to hardware limitation the overlay video will  not  work  with  the
       interlaced/doublescan   modes.   Downscaling   is  not  implemented  in

   Configuration options
       The following display Options are supported:

       Option "HWCursor" "boolean"
              Enable or  disable  the  hardware  cursor.  Currently,  hardware
              cursor  is  not  implemented,  so  the  option  will be ignored.
              Default: off (software cursor).

       Option "NoAccel" "boolean"
              Disable acceleration. Very useful for determining if the  driver
              has problems with drawing and acceleration routines. This is the
              first option to try if your server  runs  but  you  see  graphic
              corruption  on the screen. Using it decreases performance, as it
              uses software emulation for drawing operations the video  driver
              can  accelerate  with  hardware.  Default:  off (acceleration is

       Option "ShadowFB" "boolean"
              Use shadow framebuffer. Disables hardware acceleration. Use this
              option  when  the  hardware  acceleration  is  not  available or
              undesirable. Default: off.

       Option "XVideo" "boolean"
              Enable or disable Xv support. Default: on.

       The following video memory Options are supported:

       Option "slow_dram_refresh" "boolean"
              Enable three refresh cycles  per  scanline.  Default:  off  (one
              refresh cycle).

       Option "slow_edodram" "boolean"
              Switch  to  2-cycle  EDO  mode.  Try this if you encounter pixel
              corruption.  Using  this  option  will  cause  a   decrease   in
              performance. Default: off (BIOS defaults).

       Option "slow_dram" "boolean"
              For Trio and Aurora64V+ chips: increase -RAS Precharge Timing to
              3.5 MCLK.  Try  this  option  if  you  encounter  pixel  errors.
              Default: off (BIOS defaults).

       Option "slow_vram" "boolean"
              For  Vision964, Vision968 chips: increase -RAS Low Timing to 4.5
              MCLK. Default: off (BIOS defaults).


       Xorg(1), xorg.conf(5), Xserver(1), X(7)


       Thomas Roell, Mark Vojkovich, Kevin E. Martin, Amancio  Hasty,  Jon  N.
       Tombs  and  others were the original authors of driver for XFree86 3.x.
       Ani Joshi reworked driver for XFree86 4.x.  The  further  modifications
       were   made   by   the   following  contributors:  Adam  Jackson,  Alan
       Coopersmith, Dave Airlie, Andrew Radrianasulu, Paulo Cesar  Pereira  de
       Andrade,  Eric  Anholt, Sren Sandmann Pedersen, Alex Deucher, Evgeny M.
       Zubok, Daniel Stone and others.

       The manual was written by Evgeny M. Zubok <>