101 lines
4.2 KiB
Plaintext
101 lines
4.2 KiB
Plaintext
|
Kernel driver i2c-piix4
|
||
|
|
|
||
|
|
Supported adapters:
|
||
|
|
* Intel 82371AB PIIX4 and PIIX4E
|
||
|
|
* Intel 82443MX (440MX)
|
||
|
|
Datasheet: Publicly available at the Intel website
|
||
|
|
* ServerWorks OSB4, CSB5, CSB6, HT-1000 and HT-1100 southbridges
|
||
|
|
Datasheet: Only available via NDA from ServerWorks
|
||
|
|
* ATI IXP200, IXP300, IXP400, SB600, SB700 and SB800 southbridges
|
||
|
|
Datasheet: Not publicly available
|
||
|
|
* AMD Hudson-2
|
||
|
|
Datasheet: Not publicly available
|
||
|
|
* Standard Microsystems (SMSC) SLC90E66 (Victory66) southbridge
|
||
|
|
Datasheet: Publicly available at the SMSC website http://www.smsc.com
|
||
|
|
|
||
|
|
Authors:
|
||
|
|
Frodo Looijaard <frodol@dds.nl>
|
||
|
|
Philip Edelbrock <phil@netroedge.com>
|
||
|
|
|
||
|
|
|
||
|
|
Module Parameters
|
||
|
|
-----------------
|
||
|
|
|
||
|
|
* force: int
|
||
|
|
Forcibly enable the PIIX4. DANGEROUS!
|
||
|
|
* force_addr: int
|
||
|
|
Forcibly enable the PIIX4 at the given address. EXTREMELY DANGEROUS!
|
||
|
|
|
||
|
|
|
||
|
|
Description
|
||
|
|
-----------
|
||
|
|
|
||
|
|
The PIIX4 (properly known as the 82371AB) is an Intel chip with a lot of
|
||
|
|
functionality. Among other things, it implements the PCI bus. One of its
|
||
|
|
minor functions is implementing a System Management Bus. This is a true
|
||
|
|
SMBus - you can not access it on I2C levels. The good news is that it
|
||
|
|
natively understands SMBus commands and you do not have to worry about
|
||
|
|
timing problems. The bad news is that non-SMBus devices connected to it can
|
||
|
|
confuse it mightily. Yes, this is known to happen...
|
||
|
|
|
||
|
|
Do 'lspci -v' and see whether it contains an entry like this:
|
||
|
|
|
||
|
|
0000:00:02.3 Bridge: Intel Corp. 82371AB/EB/MB PIIX4 ACPI (rev 02)
|
||
|
|
Flags: medium devsel, IRQ 9
|
||
|
|
|
||
|
|
Bus and device numbers may differ, but the function number must be
|
||
|
|
identical (like many PCI devices, the PIIX4 incorporates a number of
|
||
|
|
different 'functions', which can be considered as separate devices). If you
|
||
|
|
find such an entry, you have a PIIX4 SMBus controller.
|
||
|
|
|
||
|
|
On some computers (most notably, some Dells), the SMBus is disabled by
|
||
|
|
default. If you use the insmod parameter 'force=1', the kernel module will
|
||
|
|
try to enable it. THIS IS VERY DANGEROUS! If the BIOS did not set up a
|
||
|
|
correct address for this module, you could get in big trouble (read:
|
||
|
|
crashes, data corruption, etc.). Try this only as a last resort (try BIOS
|
||
|
|
updates first, for example), and backup first! An even more dangerous
|
||
|
|
option is 'force_addr=<IOPORT>'. This will not only enable the PIIX4 like
|
||
|
|
'force' foes, but it will also set a new base I/O port address. The SMBus
|
||
|
|
parts of the PIIX4 needs a range of 8 of these addresses to function
|
||
|
|
correctly. If these addresses are already reserved by some other device,
|
||
|
|
you will get into big trouble! DON'T USE THIS IF YOU ARE NOT VERY SURE
|
||
|
|
ABOUT WHAT YOU ARE DOING!
|
||
|
|
|
||
|
|
The PIIX4E is just an new version of the PIIX4; it is supported as well.
|
||
|
|
The PIIX/PIIX3 does not implement an SMBus or I2C bus, so you can't use
|
||
|
|
this driver on those mainboards.
|
||
|
|
|
||
|
|
The ServerWorks Southbridges, the Intel 440MX, and the Victory66 are
|
||
|
|
identical to the PIIX4 in I2C/SMBus support.
|
||
|
|
|
||
|
|
If you own Force CPCI735 motherboard or other OSB4 based systems you may need
|
||
|
|
to change the SMBus Interrupt Select register so the SMBus controller uses
|
||
|
|
the SMI mode.
|
||
|
|
|
||
|
|
1) Use lspci command and locate the PCI device with the SMBus controller:
|
||
|
|
00:0f.0 ISA bridge: ServerWorks OSB4 South Bridge (rev 4f)
|
||
|
|
The line may vary for different chipsets. Please consult the driver source
|
||
|
|
for all possible PCI ids (and lspci -n to match them). Lets assume the
|
||
|
|
device is located at 00:0f.0.
|
||
|
|
2) Now you just need to change the value in 0xD2 register. Get it first with
|
||
|
|
command: lspci -xxx -s 00:0f.0
|
||
|
|
If the value is 0x3 then you need to change it to 0x1
|
||
|
|
setpci -s 00:0f.0 d2.b=1
|
||
|
|
|
||
|
|
Please note that you don't need to do that in all cases, just when the SMBus is
|
||
|
|
not working properly.
|
||
|
|
|
||
|
|
|
||
|
|
Hardware-specific issues
|
||
|
|
------------------------
|
||
|
|
|
||
|
|
This driver will refuse to load on IBM systems with an Intel PIIX4 SMBus.
|
||
|
|
Some of these machines have an RFID EEPROM (24RF08) connected to the SMBus,
|
||
|
|
which can easily get corrupted due to a state machine bug. These are mostly
|
||
|
|
Thinkpad laptops, but desktop systems may also be affected. We have no list
|
||
|
|
of all affected systems, so the only safe solution was to prevent access to
|
||
|
|
the SMBus on all IBM systems (detected using DMI data.)
|
||
|
|
|
||
|
|
For additional information, read:
|
||
|
|
http://www.lm-sensors.org/browser/lm-sensors/trunk/README.thinkpad
|