There are two different SVGA drivers for Cirrus chipsets, one called ``cirrus'' and one called ``cl64xx''. The ``cirrus'' driver is used in the 256-color SVGA server (with acceleration) and the mono server (without acceleration). The SVGA server supports 16 and 32 bits-per-pixel truecolor modes on some configurations. The ``cl64xx'' driver is used in the 256-color SVGA, 16-color and mono servers. Note that except where stated otherwise, this document is referring to the ``cirrus'' driver. The following chipsets by Cirrus Logic are supported:
ISA SVGA chipset, 1Mbyte; maximum dot clock is 45 MHz (256 color server). Acceleration with extended write modes (used for scrolling and solid filling in this driver). This chipset can not support 1024x768 non-interlaced in 256 colors.
Enhanced version of the 5420 (32-bit internal memory interface). Maximum dot clock is 80 MHz.
Laptop chipsets more or less compatible with the 5420. The
only dot clock supported is 25 MHz (more on an external
display). Some problems have been reported with these
chipsets (especially on external displays). Take note of
the "noaccel" option.
These chipsets are not compatible with the 542x series, but are
supported by the ``cl64xx'' driver. It is used in
recent laptops, and bears some similarity to old Cirrus
chipsets (5410/AVGA2). The driver may also work for other
64xx chips. The configuration identifiers for this driver are
"cl6420" and "cl6440". This driver is discussed
in detail in section
The cl64xx Driver
.
Basically VLB version of the 5422, but resembles the 5426 in some respects.
Supports both ISA bus and VLB, and up to 2Mbyte of memory. Has BitBLT engine for improved acceleration (BitBlt, image transfer, text). Dot clock limit is 85 MHz.
Enhanced version of the 5426.
Enhanced version of the 5428; officially supports higher MCLK and has memory-mapped I/O.
Similar to 5429, but with 543x core (32-bit host interface). Does not have 64-bit memory mode.
Next generation `Alpine' family chip with 64-bit internal memory interface. Used by the Orchid Kelvin 64. The chip can only support 64-bit mode if equipped with 2 Mbytes of memory; cards with only 1 Mbyte are severely limited. Support dot clocks up to 110 MHz.
Here's a list of maximum dot clocks for each supported depth:
mono 8 bpp (256c) 16 bpp____ 32 bpp
CL-GD62x5 45 MHz 45 MHz____
CL-GD5420 80 MHz 45 MHz (1)
CL-GD542x/512K 80 MHz 45 MHz____
CL-GD5422/24 80 MHz 80 MHz____ 40 MHz____
CL-GD5426/28 85 MHz 85 MHz____ 45 MHz (2)
CL-GD5429 85 MHz 85 MHz____ 50 MHz____
CL-GD5430 85 MHz 85 MHz____ 45 MHz (2)
CL-GD5434/1Mb 85 MHz 85 MHz____ 45 MHz (2)
CL-GD5434/2Mb 85 MHz 85 MHz____ 85 MHz____ 45 MHz (2)
(1) with 512K memory.
(2) 50 MHz with high MCLK setting.
Rough virtual/physical screen resolution limits for different amounts of video memory:
mono 8bpp 16 bpp 32 bpp
256K_ 800x600__ 640x400__ _________ ________
512K_ 1152x900_ 800x600__ 640x400__ ________
1024K 1600x1200 1152x900_ 800x600__ ________
2048K 2304x1728 1600x1200 1152x900_ 800x600_
4096K 2304x1728 2272x1704 1600x1200 1152x900
The virtual width must be a multiple of 32 if acceleration is used.
The horizontal monitor timings must be below 2048.
To run XF86_SVGA at 16 or 32 bpp, pass options to the X server as
follows:
startx -- -bpp 16 5-6-5 RGB ('64K color', XGA)
startx -- -bpp 16 -weight 555 5-5-5 RGB ('Hicolor')
startx -- -bpp 32 8-8-8 XRGB truecolor (5434)
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