Section "Device"
Identifier "devname"
Driver "s3"
...
[Option "optionname" ["optionvalue"]]
EndSection
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.
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.
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 xorg.conf(5):
Section "Screen"
DefaultFbBpp 24
DefaultDepth 24
...
EndSection
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.
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
hardware.
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 enabled).
- 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
<evgeny.zubok@tochka.ru>