Provided by: xserver-xorg-video-s3_0.6.3-4build2_i386 bug


       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, Søren Sandmann Pedersen, Alex Deucher, Evgeny  M.
       Zubok, Daniel Stone and others.

       The manual was written by Evgeny M. Zubok <>