xref: /xsrc/external/mit/xf86-video-s3virge/dist/README

What works: 
- Supports 8bpp, 15/16bpp, 24bpp and 32bpp. Heavy testing on ViRGE DX.
- There is some known instability in ViRGE GX2, please report problems.
- Silken Mouse is enabled by default, use the generic server option of
  -nosilk to disable it.

XCONFIG options:

The driver supports quite a few different XConfig options, which can
be used to tune the driver and improve performance. Without any options, 
the driver will use conservative settings which should work on most
hardware. Large improvements in performance are possible by selecting
the proper options, which will probably work on most systems.

Cursor:

- "hwcursor" "off" behaves exactly like "swcursor".  Default: "on"
- "swcursor" will disable the HW Cursor.  HW Cursor is used by default and
	no option is needed to enable it.

Display:
- "ShadowFB"  Use shadow framebuffer.  Disables HW acceleration.  Default: off.
- "Rotate" " cw "|" ccw "  Rotate the screen CW - clockwise or CCW - counter
    clockwise.  Disables HW Acceleration and HW Cursor, uses ShadowFB.
    Default: no rotation.
- "XVideo"  Disable XVideo support by using the off option.  This changes FIFO
    settings which prevent screen noise for high-res modes.  Default: on

Video memory:

- "slow_edodram" will switch the standard ViRGE to 2-cycle edo mode. Try this
	if you encounter pixel corruption on the ViRGE. Using this option will
	cause a large decrease in performance. 
- "fpm_vram" will switch the ViRGE/VX to fast page mode vram mode
- "slow_dram " | " fast_dram"  Change Trio 3D and 3D/2X memory options.
    Default: Use BIOS defaults.
- "early_ras_precharge", "late_ras_precharge" adjust memory parameters.  One
	of these will us the same settings as your video card defaults, and
	using neither in the config file does the same.
- "set_mclk" sets the memory clock, format is:
	Option "set_mclk" "50000" 
	in the XF86Config file.  Valid values are any 
	integer <= 100000, where 100000 == 100 MHz.
- "set_refclk" sets the ref clock for ViRGE MX, format is:
	Option "set_refclk" "50000" 

Acceleration and graphic engine:
 
- "NoAccel" turns off all acceleration
- "fifo_aggressive", "fifo_moderate" and "fifo_conservative" alter the settings
	for the threshold at which the pixel FIFO takes over the internal 
	memory bus to refill itself. The smaller this threshold, the better
	the acceleration performance of the card. You may try the fastest 
	setting ("aggressive") and move down if you encounter pixel corruption.
	The optimal setting will probably depend on dot-clock and on color 
	depth. Note that specifying any of these options will also alter other
	memory settings which should increase performance, so you should at
        least use "fifo_conservative" (this uses the chip defaults).
- Common XAA acceleration options to disable primitives for test purposes:
	"XaaNoScreenToScreenCopy"
	"XaaNoSolidFillRect"
	"XaaNoColor8x8PatternFillRect"
	"XaaNoImageWriteRect"
	"XaaNoPixmapCache"

PCI bus:
- "pci_burst" will enable PCI burst mode. This should work on all but a
	few "broken" PCI chipsets, and will increase performance.  Option may
	take a parameter "on", "off", "yes", etc...
- "pci_retry" will allow the driver to rely on PCI Retry to program the 
	ViRGE registers. "pci_burst" must be enabled for this to work. 
	This will increase performance, especially for small fills/blits, 
        because the driver does not have to poll the ViRGE before sending it 
        commands to make sure it is ready. It should work on most 
        recent PCI chipsets. 

ViRGE MX LCD options:
- "lcd_center"
- "set_lcdclk" allows setting the clock for a ViRGE MX LCD display. Format is:
	Option "set_lcdclk" "30000"
	in the config file.  Valid values are ?

Debug:
- "ShowCache"  Enable or disable viewing offscreen cache memory.  A
    development debug option.  Default: off.
- "mx_cr3a_fix"  Enable or disable a cr3a fix added for ViRGE MX.
    Default: on.


$XFree86: xc/programs/Xserver/hw/xfree86/drivers/s3virge/README,v 1.9 2000/06/14 21:57:54 dawes Exp $