1 ======================= 1 =======================
2 Kernel driver i2c-piix4 2 Kernel driver i2c-piix4
3 ======================= 3 =======================
4 4
5 Supported adapters: 5 Supported adapters:
6 * Intel 82371AB PIIX4 and PIIX4E 6 * Intel 82371AB PIIX4 and PIIX4E
7 * Intel 82443MX (440MX) 7 * Intel 82443MX (440MX)
8 Datasheet: Publicly available at the Intel 8 Datasheet: Publicly available at the Intel website
9 * ServerWorks OSB4, CSB5, CSB6, HT-1000 and 9 * ServerWorks OSB4, CSB5, CSB6, HT-1000 and HT-1100 southbridges
10 Datasheet: Only available via NDA from Ser 10 Datasheet: Only available via NDA from ServerWorks
11 * ATI IXP200, IXP300, IXP400, SB600, SB700 a 11 * ATI IXP200, IXP300, IXP400, SB600, SB700 and SB800 southbridges
12 Datasheet: Not publicly available 12 Datasheet: Not publicly available
13 SB700 register reference available at: 13 SB700 register reference available at:
14 http://support.amd.com/us/Embedded_TechDoc 14 http://support.amd.com/us/Embedded_TechDocs/43009_sb7xx_rrg_pub_1.00.pdf
15 * AMD SP5100 (SB700 derivative found on some 15 * AMD SP5100 (SB700 derivative found on some server mainboards)
16 Datasheet: Publicly available at the AMD w 16 Datasheet: Publicly available at the AMD website
17 http://support.amd.com/us/Embedded_TechDoc 17 http://support.amd.com/us/Embedded_TechDocs/44413.pdf
18 * AMD Hudson-2, ML, CZ 18 * AMD Hudson-2, ML, CZ
19 Datasheet: Not publicly available 19 Datasheet: Not publicly available
20 * Hygon CZ 20 * Hygon CZ
21 Datasheet: Not publicly available 21 Datasheet: Not publicly available
22 * Standard Microsystems (SMSC) SLC90E66 (Vic 22 * Standard Microsystems (SMSC) SLC90E66 (Victory66) southbridge
23 Datasheet: Publicly available at the SMSC 23 Datasheet: Publicly available at the SMSC website http://www.smsc.com
24 24
25 Authors: 25 Authors:
26 - Frodo Looijaard <frodol@dds.nl> 26 - Frodo Looijaard <frodol@dds.nl>
27 - Philip Edelbrock <phil@netroedge.com> 27 - Philip Edelbrock <phil@netroedge.com>
28 28
29 29
30 Module Parameters 30 Module Parameters
31 ----------------- 31 -----------------
32 32
33 * force: int 33 * force: int
34 Forcibly enable the PIIX4. DANGEROUS! 34 Forcibly enable the PIIX4. DANGEROUS!
35 * force_addr: int 35 * force_addr: int
36 Forcibly enable the PIIX4 at the given addre 36 Forcibly enable the PIIX4 at the given address. EXTREMELY DANGEROUS!
37 37
38 38
39 Description 39 Description
40 ----------- 40 -----------
41 41
42 The PIIX4 (properly known as the 82371AB) is a 42 The PIIX4 (properly known as the 82371AB) is an Intel chip with a lot of
43 functionality. Among other things, it implemen 43 functionality. Among other things, it implements the PCI bus. One of its
44 minor functions is implementing a System Manag 44 minor functions is implementing a System Management Bus. This is a true
45 SMBus - you can not access it on I2C levels. T 45 SMBus - you can not access it on I2C levels. The good news is that it
46 natively understands SMBus commands and you do 46 natively understands SMBus commands and you do not have to worry about
47 timing problems. The bad news is that non-SMBu 47 timing problems. The bad news is that non-SMBus devices connected to it can
48 confuse it mightily. Yes, this is known to hap 48 confuse it mightily. Yes, this is known to happen...
49 49
50 Do ``lspci -v`` and see whether it contains an 50 Do ``lspci -v`` and see whether it contains an entry like this::
51 51
52 0000:00:02.3 Bridge: Intel Corp. 82371AB/EB/ 52 0000:00:02.3 Bridge: Intel Corp. 82371AB/EB/MB PIIX4 ACPI (rev 02)
53 Flags: medium devsel, IRQ 9 53 Flags: medium devsel, IRQ 9
54 54
55 Bus and device numbers may differ, but the fun 55 Bus and device numbers may differ, but the function number must be
56 identical (like many PCI devices, the PIIX4 in 56 identical (like many PCI devices, the PIIX4 incorporates a number of
57 different 'functions', which can be considered 57 different 'functions', which can be considered as separate devices). If you
58 find such an entry, you have a PIIX4 SMBus con 58 find such an entry, you have a PIIX4 SMBus controller.
59 59
60 On some computers (most notably, some Dells), 60 On some computers (most notably, some Dells), the SMBus is disabled by
61 default. If you use the insmod parameter 'forc 61 default. If you use the insmod parameter 'force=1', the kernel module will
62 try to enable it. THIS IS VERY DANGEROUS! If t 62 try to enable it. THIS IS VERY DANGEROUS! If the BIOS did not set up a
63 correct address for this module, you could get 63 correct address for this module, you could get in big trouble (read:
64 crashes, data corruption, etc.). Try this only 64 crashes, data corruption, etc.). Try this only as a last resort (try BIOS
65 updates first, for example), and backup first! 65 updates first, for example), and backup first! An even more dangerous
66 option is 'force_addr=<IOPORT>'. This will not 66 option is 'force_addr=<IOPORT>'. This will not only enable the PIIX4 like
67 'force' does, but it will also set a new base 67 'force' does, but it will also set a new base I/O port address. The SMBus
68 parts of the PIIX4 needs a range of 8 of these 68 parts of the PIIX4 needs a range of 8 of these addresses to function
69 correctly. If these addresses are already rese 69 correctly. If these addresses are already reserved by some other device,
70 you will get into big trouble! DON'T USE THIS 70 you will get into big trouble! DON'T USE THIS IF YOU ARE NOT VERY SURE
71 ABOUT WHAT YOU ARE DOING! 71 ABOUT WHAT YOU ARE DOING!
72 72
73 The PIIX4E is just an new version of the PIIX4 73 The PIIX4E is just an new version of the PIIX4; it is supported as well.
74 The PIIX/PIIX3 does not implement an SMBus or 74 The PIIX/PIIX3 does not implement an SMBus or I2C bus, so you can't use
75 this driver on those mainboards. 75 this driver on those mainboards.
76 76
77 The ServerWorks Southbridges, the Intel 440MX, 77 The ServerWorks Southbridges, the Intel 440MX, and the Victory66 are
78 identical to the PIIX4 in I2C/SMBus support. 78 identical to the PIIX4 in I2C/SMBus support.
79 79
80 The AMD SB700, SB800, SP5100 and Hudson-2 chip 80 The AMD SB700, SB800, SP5100 and Hudson-2 chipsets implement two
81 PIIX4-compatible SMBus controllers. If your BI 81 PIIX4-compatible SMBus controllers. If your BIOS initializes the
82 secondary controller, it will be detected by t 82 secondary controller, it will be detected by this driver as
83 an "Auxiliary SMBus Host Controller". 83 an "Auxiliary SMBus Host Controller".
84 84
85 If you own Force CPCI735 motherboard or other 85 If you own Force CPCI735 motherboard or other OSB4 based systems you may need
86 to change the SMBus Interrupt Select register 86 to change the SMBus Interrupt Select register so the SMBus controller uses
87 the SMI mode. 87 the SMI mode.
88 88
89 1) Use ``lspci`` command and locate the PCI de 89 1) Use ``lspci`` command and locate the PCI device with the SMBus controller:
90 00:0f.0 ISA bridge: ServerWorks OSB4 South 90 00:0f.0 ISA bridge: ServerWorks OSB4 South Bridge (rev 4f)
91 The line may vary for different chipsets. P 91 The line may vary for different chipsets. Please consult the driver source
92 for all possible PCI ids (and ``lspci -n`` 92 for all possible PCI ids (and ``lspci -n`` to match them). Let's assume the
93 device is located at 00:0f.0. 93 device is located at 00:0f.0.
94 2) Now you just need to change the value in 0x 94 2) Now you just need to change the value in 0xD2 register. Get it first with
95 command: ``lspci -xxx -s 00:0f.0`` 95 command: ``lspci -xxx -s 00:0f.0``
96 If the value is 0x3 then you need to change 96 If the value is 0x3 then you need to change it to 0x1:
97 ``setpci -s 00:0f.0 d2.b=1`` 97 ``setpci -s 00:0f.0 d2.b=1``
98 98
99 Please note that you don't need to do that in 99 Please note that you don't need to do that in all cases, just when the SMBus is
100 not working properly. 100 not working properly.
101 101
102 102
103 Hardware-specific issues 103 Hardware-specific issues
104 ------------------------ 104 ------------------------
105 105
106 This driver will refuse to load on IBM systems 106 This driver will refuse to load on IBM systems with an Intel PIIX4 SMBus.
107 Some of these machines have an RFID EEPROM (24 107 Some of these machines have an RFID EEPROM (24RF08) connected to the SMBus,
108 which can easily get corrupted due to a state 108 which can easily get corrupted due to a state machine bug. These are mostly
109 Thinkpad laptops, but desktop systems may also 109 Thinkpad laptops, but desktop systems may also be affected. We have no list
110 of all affected systems, so the only safe solu 110 of all affected systems, so the only safe solution was to prevent access to
111 the SMBus on all IBM systems (detected using D 111 the SMBus on all IBM systems (detected using DMI data.)
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