savage - S3 Savage video driver
savage is an Xorg driver for the S3 Savage family video
accelerator chips. 2D, 3D, and Xv acceleration is supported on all chips
except the Savage2000 (2D only). Dualhead operation is supported on MX, IX,
and SuperSavage chips. The savage driver supports PCI and AGP boards
with the following chips:
- (8a20 and 8a21) (2D, 3D)
- (8a22) (2D, 3D)
- (9102) (2D only)
- (8c10 and 8c11) (2D, 3D, Dualhead)
- (8c12 and 8c13) (2D, 3D, Dualhead)
- (8c22, 8c24, and 8c26) (2D, 3D, Dualhead)
- (8c2a, 8c2b, 8c2c, 8c2d, 8c2e, and 8c2f) (2D, 3D, Dualhead)
- (8a25) (2D, 3D)
- (8a26) (2D, 3D)
- Twister (ProSavage
- (8d01) (2D, 3D)
- TwisterK (ProSavage
- (8d02) (2D, 3D)
- (8d03) (2D, 3D)
- (8d04) (2D, 3D)
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:
- These two options interact to specify hardware or software cursor. If the
SWCursor option is specified, any HWCursor setting is ignored. Thus,
either "HWCursor off" or "SWCursor on" will force the
use of the software cursor. On Savage/MX and Savage/IX chips which are
connected to LCDs, a software cursor will be forced, because the Savage
hardware cursor does not correctly track the automatic panel expansion
feature. Default: hardware cursor.
- Disable or enable acceleration. Default: acceleration is enabled.
- Chooses between available acceleration architectures. Valid options are
XAA and EXA. XAA is the traditional acceleration
architecture and support for it is very stable. EXA is a newer
acceleration architecture with better performance for the Render and
Composite extensions, but the rendering code for it is newer and possibly
unstable. The default is XAA.
- Rotate the desktop 90 degrees clockwise or counterclockwise. This option
forces the ShadowFB option on, and disables acceleration and the RandR
extension. Default: no rotation.
- Enable or disable use of the shadow framebuffer layer. This option
disables acceleration. Default: off.
- Override the maximum dot clock. Some LCD panels produce incorrect results
if they are driven at too fast of a frequency. If UseBIOS is on, the BIOS
will usually restrict the clock to the correct range. If not, it might be
necessary to override it here. The frequency parameter may be
specified as an integer in Hz (135750000), or with standard suffixes like
"k", "kHz", "M", or "MHz" (as in
- This option disables output to the LCD and enables output to the CRT port
only. It is useful on laptops if you only want to use the CRT port or to
force the CRT output only on desktop cards that use mobile chips. Default:
auto-detect active outputs
- Enable or disable use of the video BIOS to change modes. Ordinarily, the
savage driver tries to use the video BIOS to do mode switches. This
generally produces the best results with the mobile chips (/MX and /IX),
since the BIOS knows how to handle the critical but unusual timing
requirements of the various LCD panels supported by the chip. To do this,
the driver searches through the BIOS mode list, looking for the mode which
most closely matches the xorg.conf mode line. Some purists find this
scheme objectionable. If you would rather have the savage driver
use your mode line timing exactly, turn off the UseBios option.
Note: Use of the BIOS is required for dualhead operation. Default:
on (use the BIOS).
- Do not use EDID data for mode validation, but DDC is still used for
monitor detection. This is different from NoDDC option.
The default value is off.
- Enables the use of a shadow status register. There is a chip bug in the
Savage graphics engine that can cause a bus lock when reading the engine
status register under heavy load, such as when scrolling text or dragging
windows. The bug affects about 4% of all Savage users without DRI and a
large fraction of users with DRI. If your system hangs regularly while
scrolling text or dragging windows, try turning this option on. This uses
an alternate method of reading the engine status which is slightly more
expensive, but avoids the problem. When DRI is enabled then the default is
"on" (use shadow status), otherwise the default is
"off" (use normal status register).
- Disables the COB (Command Overflow Buffer) on savage4 and newer chips.
There is supposedly a HW cache coherency problem on certain savage4 and
newer chips that renders the COB useless. If you are having problems with
2D acceleration you can disable the COB, however you will lose some
performance. 3D acceleration requires the COB to work. This option only
applies to Savage4 and newer chips. Default: "off" (use
- Use the BCI to copy and reformat Xv pixel data. Using the BCI for Xv
causes graphics artifacts on some chips. This option only applies to
Savage4 and prosavage/twister chips. On some combinations of chipsets and
video players, BCI formatting might actually be slower than software
formatting ("AGPforXv" might help in this case). BCI formatting
can only be used on video data with a width that is a multiple of 16
pixels (which is the vast majority of videos). Other widths are handled
through software formatting. Default: on for prosavage and twister (use
BCI for Xv); off for savage4 (do not use the BCI for Xv).
- Instructs the BCI Xv pixel formatter to use AGP memory as a scratch
buffer. Ordinarily the BCI formatter uses a an area in framebuffer memory
to hold YV12 planar data to be converted for display. This requires a
somewhat expensive upload of YV12 data to framebuffer memory. The
"AGPforXv" option causes the BCI formatter to place the YV12
data in AGP memory instead, which can be uploaded faster than the
framebuffer. Use of this option cuts upload overhead by 25% according to
benchmarks. This option also smooths out most of the shearing present when
using BCI for pixel conversion. Currently this option is
experimental and is disabled by default. Video width restrictions
that apply to "BCIforXv" also apply here. Only valid when
"DRI" and "BCIforXv" are both active, and only on AGP
chipsets. Default: "off".
If "AccelMethod" is set to "EXA" and
"AGPforXv" is enabled, then the driver will also attempt to
reuse the AGP scratch buffer for UploadToScreen acceleration.
- Set AGP data transfer rate. (used only when DRI is enabled)
1 -- x1 (default)
2 -- x2
4 -- x4
others -- invalid
- The amount of AGP memory that will allocated for DMA and textures in MB.
Valid sizes are 4, 8, 16, 32, 64, 128 and 256. The default is 16MB.
- This option influences in which way DMA (direct memory access) is used by
the kernel and 3D drivers.
Any -- Try command DMA first, then vertex DMA (default)
Command -- Only use command DMA or don't use DMA at all
Vertex -- Only use vertex DMA or don't use DMA at all
None -- Disable DMA
Command and vertex DMA cannot be enabled at the same time. Which DMA mode is
actually used in the end also depends on the DRM version (only >= 2.4.0
supports command DMA) and the hardware (Savage3D/MX/IX doesn't support
- The type of memory that will be used by the 3D driver for DMA (direct
PCI -- PCI memory (default on PCI cards)
AGP -- AGP memory (default on AGP cards)
"AGP" only works if you have an AGP card.
- The bus type that will be used to access the graphics card.
PCI -- PCI bus (default on PCI cards)
AGP -- AGP bus (default on AGP cards)
"AGP" only works if you have an AGP card. If you choose
"PCI" on an AGP card the AGP bus speed is not set and no AGP
aperture is allocated. This implies DmaType "PCI".
- Enable DRI support. This option allows you to enable or disable the DRI.
Default: "on" (enable DRI).
Xorg(1), xorg.conf(5), Xserver(1), X(7)
Authors include Tim Roberts (firstname.lastname@example.org) and Ani Joshi
(email@example.com) for this version, and Tim Roberts and S. Marineau for
the original driver from which this was derived.