Notes for Mach32 X Server Bryan Feir (jenora@istar.ca) 2 July 1997 1. Supported Cards, RAMDACs, and Bits Per Pixel The base support in the Mach32 X server is for 8 bpp, with a dot clock of up to 80 MHz. At present 15/16 bpp is supported on only three of the many RAM- DACs; however those three cover the most commonly sold cards. RAMDAC Max Dot Clock BPP Max Resolution Video RAM Required -------- ------------- --- -------------- ------------------ Default 80MHz 8 1280x1024i 2Mb Default 80MHz 8 1024x768 1Mb ATI68875 135MHz 8 1280x1024 2Mb ATI68875 80MHz 16 1024x768 2Mb AT&T20C49x 80MHz 8 1024x768 1Mb AT&T20C49x 40MHz 16 800x600 2Mb BT481 80MHz 8 1024x768 1Mb BT481 40MHz 16 800x600 2Mb The RAMDAC is reported when you run the Mach32 X server with the "-probeonly" command line option, or can be specified in the XF86Config file. The ATI68875 (or the TLC34075) is used on the Graphics Ultra + and the Graph- ics Ultra Pro. The Brooktree 481 is used on most Graphics Wonder cards. The AT&T20C491 is used on many of the OEM cards that are built into component systems. The BIOS detection unfortunately lumps the BT481 and the AT&T20C49x together, while they require different configuration controls in 16 bit mode. Super- Probe can tell the difference, and will report which it finds. In the server itself, the BT481 is considered the default value. If you have an AT&TC49x RAMDAC on your card you will have to include the Ramdac entry in the XF86Con- fig file as below. 2. XF86Config options Several options are supported in the "Device" section for the Mach32 X server. Most of them should be auto-detected if needed, but a few may need to be deliberately set. For example, the "Clocks" entry should almost cer- tainly be set after first running the server with the -probeonly option, so as to avoid the probe in later runs. Option "composite" This option will set the composite sync for monitors that require this. Option "dac_8_bit" This option enables 8 bits per RGB value. Note this option does not work with all RAMDACs, and is not considered supported by the Mach32 itself. Option "ast_mach32" This option sets some special handling for the AST version of the Mach32 card that comes soldered in to some of their motherboards. This card will lock up without this option. Option "intel_gx" This option sets the memory aperture address to the hardwired value for the Intel GX Pro. It is equivalent to setting Membase to 0x78000000. Option "no_linear" This option disables the use of the linear mapped framebuffer. This should be auto-detected. Option "sw_cursor" This option allows you to use the software cursor instead of the hardware cursor. MemBase baseaddress This entry specifies the video memory aperture address. Normally the aperture address is automatically determined, but on some VESA Local Bus systems the address chosen will not work. If the Mach32 X server is dying with a seg. fault, then try setting the aperture address to another location. Clocks clock ... This entry gives the clock rates for the server to use. Ramdac "type" This entry specifies the RAMDAC type. The following values are valid for type: o ati68830 o sc11483 o sc11486 o sc11488 o ims_g173 o mu9c4870 o ati68875* o bt885 o tlc34075* o bt476 o bt478 o inmos176 o inmos178 o bt481* o bt482 o ims_g174 o mu9c1880 o mu9c4910 o sc15025 o sc15026 o att20c490* o ati68860 o stg1700 o sc15021 o stg1702 o att21c498 Only the ones marked with [*] have an effect yet. 3. Known Problems and Bug Reports There are several known problems with the current version of the Mach32 X server. They include: o Not all RAMDACs are supported at higher colour ranges, and not all that are can be detected properly. In fact most of the RAMDAC values above have no effect except to block higher bit modes. o Sixteen bit character support (e.g., Chinese and Japanese character sets) has been known to lose parts of characters. While this should be fixed, if it occurs try running the server with Option "no_linear". Bug reports should be sent to XFree86@XFree86.org or posted to the comp.win- dows.x.i386unix newsgroup. Generated from XFree86: xc/programs/Xserver/hw/xfree86/doc/sgml/Mach32.sgml,v 3.5.2.3 1998/11/07 13:37:47 dawes Exp $ $XConsortium: Mach32.sgml /main/4 1996/10/28 04:47:43 kaleb $