1WARNING:
2On exit XFree86 restores the old mode but it
3does not disable the secondary card. As a result
4the second card (which has some randonm CRTC timing)
5may produce synch pulses which are wrong for your
6monitor.
7
8If your monitor does not tolerate bad timing I would
9recommend that you don't try Multi-head yet, or at
10least, turn it off *before* leaving X.
11
12
133.9Nl notice: There is a problem with releasing
14of LBX colormap privates which may cause a seg.
15fault when the server exits. I got a patch from
16Mark Vojkovich which fixes it.
17
18If you have a CL-GD5480 or CL-GD5446 ver. B you
19should be able to try Multi-Head with that
20card as a secondary. The primary card should not
21have any special feature. Some MainBoards may
22not do it right too. I tried it with a 5465 (AGP)
23as a primary and 5446B (PCI) secondary on an
24ABIT LX6 upgraded to the latest bios.
25
26Version A of the 5446 cannot be pure MMIO (The driver 
27requires that it is the primary display adapter).
28You can distinguish between the rel A and rel B by
29running "scanpci -v". Version 1 does not report a
30valid BASE1 address.
31
32The bios upgrade lets me chose if the primary
33display adapter is on PCI on AGP (I chose
34the AGP card as primary). Warning - this setup
35will *NOT* work with XFree86 3.3.2.
36
37The only problem that I found so far is with
38memory configuration initialization. My bios
39does not initialize the secondary display adapter.
40This results in a corrupted display.
41
42Here are the options:
431. warm booting from Windows 98 may work. I have
44not tried that.
45
462. Take out the other card and leave the 5446
47(or 5480) as the primary card. Start the server
48and watch it's output. Look for lines like:
49  (--) CIRRUS(0): Memory Config reg 1 is 0x1B
50  (--) CIRRUS(0): Memory Config reg 2 is 0x21
51Remember these values. Now edit XF86Config
52and add to the proper device section the lines:
53  Option "MemCFG1" "0x1B"
54  Option "MemCFG2" "0x21"
55These values are the contents of registers SR0F
56and SR17. (notice: the 5480 driver does not use
57and will not print MemCFG2).
58
59Now you can reinstall the other card (which
60must me set as the the primary display adaptor).
61
62A note about configuring multi-head:
63There should be a separate section for each
64adapter (device), Monitor and Screen. A "ServerLayout"
65section is optional (and recommended). To make it
66easier for XFree86 to relate device sections to
67actual cards, use a BusId line in each device
68section. XFree86 3.9N works properly if the config
69file is for Multi-head but it finds only one
70display adapter.
71