voodoo
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 (SLI).
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.
CONFIGURATION DETAILS
Please refer to xorg.conf(5) for general configuration
details. This section only covers configuration details specific to this
driver.
The following driver
Options
are supported:
Option N'34'ShadowFBN'34' N'34'booleanN'34'
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 N'34'NoAccelN'34' N'34'booleanN'34'
Disables acceleration if set. Unless debugging this option should only
be set if ShadowFB is enabled.
Default: off for voodoo2, on for voodoo1.
BUGS
The driver interacts badly with the
sstfb frame buffer driver as there is insufficient information to restore
the chip to its previous state.
