1 Information for Trident Chipset Users 2 ------------------------------------- 3 4Contents 5-------- 6 1) Supported chipsets 7 2) Special considerations for 512k boards 8 3) Additional notes 9 101 - Supported chipsets 11---------------------- 12 The Trident driver has undergone major work between XFree86 1.2 and 13XFree86 1.3. Because of this work, all of the Trident SVGA chipsets, except 14the very first one, are supported by both the color and monochrome servers. 15Specifically, the following chipsets are supported: 16 17 8800CS 18 8900B 19 8900C 20 8900CL 21 9000 22 23The original Trident chipset, 8800BR, cannot be supported as an SVGA chipset 24by either the color or monochrome servers. The chip is supported, however, 25by the "generic" driver for the monochrome server. 26 272 - Special considerations for 512k boards 28------------------------------------------ 29 512k cards require the clocks in the ModeDB entries to be double the normal 30value when operating in 256 color mode. This doubled clock must be a clock 31value on the card. The reason for this is that each pixel takes two clock 32cycles in 256 color mode. 33 34To create timings for the color modes, take the timings for the corresponding 35monochrome mode, and double the clock. For example: 36 37 monochrome timings (taken from Xconfig.sample): 38 "640x480" 25 640 664 760 800 480 491 493 525 39 "800x600" 36 800 824 896 1024 600 601 603 625 40 41 color timings: 42 "640x480c" 50 640 664 760 800 480 491 493 525 43 "800x600c" 72 800 824 896 1024 600 601 603 625 44 45Be aware that older Trident chipsets support a maximum clock of 65Mhz. Hence 46the best actual clock available to the color server is 32.5Mhz. This means, 47in broad terms, that the color server will require an interlaced mode to be 48defined for resolutions above 640x480. Newer chipsets (8900CL and 9000) 49support up to 16 clocks, and can support much higher clocks, which will allow 50800x600 modes, non-interlaced. 51 523 - Additional Notes 53-------------------- 54 We have had reports of the server failing to detect the amount of installed 55memory and the correct dot-clocks on older TVGA8900 boards. If the server 56fails to detect the correct amount of memory, use the "Videoram" keyword in 57your Xconfig file to specify it. (e.g. Videoram 512 or Videoram 1024). If 58the server has problems detecting the dot-clocks, try adding the following 59line to your Xconfig file: 60 61 Clocks 25 28 45 36 57 65 50 40 62 63This line gives the clock values provided by older Trident clock synthesizer 64chipsets. This also appears to be the standard first 8 clocks for the newer 65clock synthesizers, but you should have no problems on newer boards. 66 67 Some newer Trident 8900B/C boards are apparently being built with the clock 68synthesizers used on the 9000 and 8900CL boards. If your board has a chip 69labeled "Trident TCK900x" ("x" has been seen as 2 or 4; there may be others), 70your board may actually have a 4th clock select bit. The 9002 has twelve 71distinct clocks (the other 4 are duplicates); the 9004 has 16 clocks (the 72same 12 as the 9002 + 4 others). If you see such a chip on a board with 73an 8900B or 8900C, put the following line in your Xconfig file after the 74"vga256" and/or "vga2" line: 75 76 Option "16clocks" 77 78This will cause the same clock selection code as is used for the 8900CL to 79be used for the board. 80 81 While developing the Trident driver, an interesting and perturbing hardware 82phenomenon was discovered. When using the default board jumper configuration, 83dot-clocks above 57Mhz would frequently lock up the machine. There appear 84to be jumpers on all of the Trident boards that determine whether the 85board will operate in zero-wait-state mode on the ISA bus. Disabling the 86zero-wait-state mode via jumpers cured the lockups, but at the expense 87of performance. Whether or not a given system will experience this problem 88is likely a combination of (a) bus speed, (b) video memory speed, and (c) dot 89clock speed. So be prepared for this phenomenon to occur, and have the board 90documentation handy. 91 92$XFree86: mit/server/ddx/x386/etc/README.trident,v 1.8 1993/05/04 10:18:10 dawes Exp $ 93