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diff --git a/README.multihead b/README.multihead new file mode 100644 index 0000000..efe62d4 --- /dev/null +++ b/README.multihead @@ -0,0 +1,70 @@ +WARNING: +On exit XFree86 restores the old mode but it +does not disable the secondary card. As a result +the second card (which has some randonm CRTC timing) +may produce synch pulses which are wrong for your +monitor. + +If your monitor does not tolerate bad timing I would +recommend that you don't try Multi-head yet, or at +least, turn it off *before* leaving X. + + +3.9Nl notice: There is a problem with releasing +of LBX colormap privates which may cause a seg. +fault when the server exits. I got a patch from +Mark Vojkovich which fixes it. + +If you have a CL-GD5480 or CL-GD5446 ver. B you +should be able to try Multi-Head with that +card as a secondary. The primary card should not +have any special feature. Some MainBoards may +not do it right too. I tried it with a 5465 (AGP) +as a primary and 5446B (PCI) secondary on an +ABIT LX6 upgraded to the latest bios. + +Version A of the 5446 cannot be pure MMIO (The driver +requires that it is the primary display adapter). +You can distinguish between the rel A and rel B by +running "scanpci -v". Version 1 does not report a +valid BASE1 address. + +The bios upgrade lets me chose if the primary +display adapter is on PCI on AGP (I chose +the AGP card as primary). Warning - this setup +will *NOT* work with XFree86 3.3.2. + +The only problem that I found so far is with +memory configuration initialization. My bios +does not initialize the secondary display adapter. +This results in a currupted display. + +Here are the options: +1. warm booting from Windows 98 may work. I have +not tried that. + +2. Take out the other card and leave the 5446 +(or 5480) as the primary card. Start the server +and watch it's output. Look for lines like: + (--) CIRRUS(0): Memory Config reg 1 is 0x1B + (--) CIRRUS(0): Memory Config reg 2 is 0x21 +Remember these values. Now edit XF86Config +and add to the proper device section the lines: + Option "MemCFG1" "0x1B" + Option "MemCFG2" "0x21" +These values are the contents of registers SR0F +and SR17. (notice: the 5480 driver does not use +and will not print MemCFG2). + +Now you can reinstall the other card (which +must me set as the the primary display adaptor). + +A note about configuring multi-head: +There should be a separate section for each +adapter (device), Monitor and Screen. A "ServerLayout" +section is optional (and recommended). To make it +easier for XFree86 to relate device sections to +actual cards, use a BusId line in each device +section. XFree86 3.9N works properly if the config +file is for Multi-head but it finds only one +display adapter. |