voodoo - Voodoo video driver
is an Xorg driver for Voodoo 1 and Voodoo 2 series video adapters.
On the Voodoo 1 the driver uses a shadow buffer in system memory as the video
adapter has only 3D acceleration. Selected portions of the shadow framebuffer
are copied out to the Voodoo board at the right time. Because of this, the
speed of the driver is very dependent on the CPU. Processors nowadays are
actually rather fast at moving data so we get very good speed anyway as the
shadow framebuffer is in cached RAM.
The Voodoo2 has 16bpp acceleration and the driver provides accelerated versions
of most operations except angled lines and stipples. Accelerated alpha
blending with the Render extension is also supported as is DGA.
This driver supports 16bpp modes currently. The video hardware supports image
conversion from 24bpp to 16bpp but the hardware is 16bpp only.
The Voodoo 1 series cards can go up to 800x600 resolution while the Voodoo 2 can
reach 1024x768 providing it has at least 2Mb of frame buffer memory. 1024x768
2D mode does not require two cards configured in scan-line interleave mode
Multihead and Xinerama configurations are supported. SLI configurations will be
treated as multiple video cards.
Limited support for DPMS screen saving is available. The "standby" and
"suspend" modes are just painting the screen black. The
"off" mode turns the Voodoo board off and thus works correctly.
This driver does not support a virtual screen size different from the display
size. This is a hardware limitation. 3D rendering is also not supported.
Please refer to xorg.conf(5) for general configuration details. This section
only covers configuration details specific to this driver.
The following driver Options
- Option "ShadowFB" "boolean"
- Enables a shadow buffer in main memory. This turns off acceleration but
for otherwise unaccelerated operations can improve performance materially.
Default: off for voodoo2, on for voodoo1.
- Option "NoAccel" "boolean"
- Disables acceleration if set. Unless debugging this option should only be
set if ShadowFB is enabled. Default: off for voodoo2, on for voodoo1.
The driver interacts badly with the sstfb frame buffer driver as there is
insufficient information to restore the chip to its previous state.
Xorg(1), xorg.conf(5), Xserver(1), X(7)
Authors: Alan Cox, Ghozlane Toumi, Henrik Harmsen.