root/lm-sensors/trunk/doc/busses/i2c-piix4 @ 1155

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update serverworks match string

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1Kernel driver `i2c-piix4.o'
2
3Status: Complete and well-tested
4
5Supported adapters:
6  * Intel 82371AB PIIX4 and PIIX4E
7    Datasheet: Publicly available at the Intel website
8  * ServerWorks OSB4 and CSB5 southbridges
9    Datasheet: only available via NDA from ServerWorks
10
11Author: Frodo Looijaard <frodol@dds.nl> and Philip Edelbrock
12        <phil@netroedge.com>
13
14
15Module Parameters
16-----------------
17
18* force: int
19  Forcibly enable the PIIX4. DANGEROUS!
20* force_addr: int
21  Forcibly enable the PIIX4 at the given address. EXTREMELY DANGEROUS!
22
23
24Description
25-----------
26
27The PIIX4 (properly known as the 82371AB) is an Intel chip with a lot of
28functionality. Among other things, it implements the PCI bus. One of its
29minor functions is implementing a System Management Bus. This is a true
30SMBus - you can not access it on I2C levels. The good news is that it
31natively understands SMBus commands and you do not have to worry about
32timing problems. The bad news is that non-SMBus devices connected to it
33can confuse it mightily. Yes, this is known to happen...
34
35Cat /proc/pci, and see whether it contains an entry like this:
36
37  Bus  0, device   1, function  3:
38    Bridge: Intel 82371AB PIIX4 ACPI (rev 1).
39      Medium devsel.  Fast back-to-back capable. 
40
41Bus and device numbers may differ, but the function number must be identical
42(like many PCI devices, the PIIX4 incorporates a number of different
43'functions', which can be considered as separate devices). If you find such
44an entry, you have a PIIX4 SMBus controller.
45
46On some computers (most notably, some Dells), the SMBus is disabled by
47default. If you use the insmod parameter 'force=1', the kernel module
48 will try to enable it. THIS IS VERY DANGEROUS! If the BIOS did not
49set up a correct address for this module, you could get in big trouble
50(read: crashes, data corruption, etc.). Try this only as a last resort
51(try BIOS updates first, for example), and backup first! An even more
52dangerous option is 'force_addr=<IOPORT>'. This will not only enable the
53PIIX4 like 'force' foes, but it will also set a new base I/O port address.
54The SMBus parts of the PIIX4 needs a range of 8 of these addresses to
55function correctly. If these addresses are already reserved by some other
56device, you will get into big trouble! DON'T USE THIS IF YOU ARE NOT VERY
57SURE ABOUT WHAT YOU ARE DOING!
58
59The PIIX4E is just an new version of the PIIX4; it is supported as well. The
60PIIX/PIIX3 does not implement an SMBus or I2C bus, so you can't use this
61driver on those mainboards.
62
63The ServerWorks Southbridges are identical to the PIIX4 in I2C support.
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