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, 24, 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.
`Alpine' family chip with 64-bit internal memory interface. The chip can only support 64-bit mode if equipped with 2 Mbytes of memory; cards with only 1 Mbyte are severely limited. Supports dot clocks up to 110 MHz (later chips support 135 MHz).
Highly optimized 5434.
Similar to the CL-GD5430, and detected as such.
Another member of the Alpine family of 2D accelerators; similar to the CL-GD5436.
Newer Alpine family chip that support synchronous graphics RAM (SGRAM).
The Laguna VisualMedia family of 2D Accelerators. These chips use Rambus RDRAM memory. The '62 is a 64-bit 2D accelerator, including a BitBlit engine, video windows (not currently used by the server), and 64x64 HW cursor. Mono modes have not been tested. The CL-GD5464 is the next chip in the Laguna family, and the CL-GD5465 is the latest member, both have been tested.
Laptop chipsets more or less compatible with the 5428/3x. While has it been tested on some configurations, not all configuration may work correctly.
Limited untested support, without auto-detection, has been provided for this chip which is a 64-bit extension of the 754x family. Use a Chipset "clgd7555" line.
Here's a list of maximum dot clocks for each supported depth:
mono 8 bpp (256c) 16 bpp 24 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 27 MHz
CL-GD5426/28 85 MHz 85 MHz 45 MHz (2) 28 MHz
CL-GD5429 85 MHz 85 MHz 50 MHz 28 MHz
CL-GD5430 85 MHz 85 MHz 45 MHz (2) 28 MHz
CL-GD5434/1Mb 85 MHz 85 MHz 42 MHz 28 MHz
CL-GD5434/2Mb 85 MHz 110/135 MHz 85 MHz 28 MHz 45/50 MHz (2)
CL-GD5436/1Mb 85 MHz 110 MHz (3) 60 MHz (3) 40 MHz (3)
CL-GD5436/2Mb 85 MHz 135 MHz 85 MHz 85 MHz (3) 60 MHz (3)
CL-GD5446/1Mb 85 MHz 110 MHz (3) 60 MHz (3) 40 MHz (3)
CL-GD5446/2Mb 85 MHz 135 MHz 85 MHz 85 MHz (3) 60 MHz (3)
CL-GD5462 170 MHz 170 Mhz 170 MHz 170 MHz 135 MHz
CL-GD5464/65 170 MHz 230 Mhz 170 MHz 170 MHz 135 MHz
CL-GD5480 85 MHz 200 MHz 100 MHz 100 MHz 50 MHz
CL-GD754x 80 MHz 80 MHz 40 MHz (4) (5)
(1) with 512K memory.
(2) 50 MHz with high MCLK setting.
(3) Depends on memory clock.
(4) This may be too low for some chips.
(5) This depth may actually work if it is enabled and tested.
Rough virtual/physical screen resolution limits for different amounts of video memory:
mono 8 bpp 16 bpp 24 bpp 32 bpp
256K 800x600 640x400
512K 1152x900 800x600 640x400
1024K 1600x1200 1152x900 800x600 680x510
2048K 2304x1728 1600x1200 1152x900 960x720 800x600
4096K 2304x1728 2272x1704 1600x1200 1360x1020 1152x900
For 546x chips, the above table isn't quite accurate. While the virtual
width may be any size, the screen pitch will be rounded up to the
nearest value in the table
below. Thus, each line on the screen will take more video memory than just
what is displayed. To maximize video memory, then, choose the virtual
desktop width from the table of pixel widths below:
8bpp: 640, 1024, 1280, 1664, 2048, 2560, 3328, 4096, 5120, 6656 16bpp: 320, 512, 640, 832, 1024, 1280, 1664, 2048, 2560, 3328 24bpp: 640, 1024, 1280, 1664, 2048, 2560, 3328, 4096, 5120, 6656 32bpp: 160, 256, 320, 416, 512, 640, 832, 1024, 1280, 1664
For other Cirrus chips, it's advisable to have a virtual width that is a multiple of 32 if acceleration is used. The horizontal monitor timings must be below 2048.
To run XF86_SVGA at a higher color depth, 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') (not on 5462)
startx -- -bpp 24 8-8-8 RGB truecolor
startx -- -bpp 32 8-8-8 XRGB truecolor (543X/46/6X only)