diff options
Diffstat (limited to 'Documentation/i2c/busses/i2c-piix4')
| -rw-r--r-- | Documentation/i2c/busses/i2c-piix4 | 40 |
1 files changed, 33 insertions, 7 deletions
diff --git a/Documentation/i2c/busses/i2c-piix4 b/Documentation/i2c/busses/i2c-piix4 index a1c8f581afe..92147633323 100644 --- a/Documentation/i2c/busses/i2c-piix4 +++ b/Documentation/i2c/busses/i2c-piix4 @@ -6,6 +6,8 @@ Supported adapters: Datasheet: Publicly available at the Intel website * ServerWorks OSB4, CSB5, CSB6 and HT-1000 southbridges Datasheet: Only available via NDA from ServerWorks + * ATI IXP southbridges IXP200, IXP300, IXP400 + Datasheet: Not publicly available * Standard Microsystems (SMSC) SLC90E66 (Victory66) southbridge Datasheet: Publicly available at the SMSC website http://www.smsc.com @@ -21,8 +23,6 @@ Module Parameters Forcibly enable the PIIX4. DANGEROUS! * force_addr: int Forcibly enable the PIIX4 at the given address. EXTREMELY DANGEROUS! -* fix_hstcfg: int - Fix config register. Needed on some boards (Force CPCI735). Description @@ -63,10 +63,36 @@ 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 Victory766 are +The ServerWorks Southbridges, the Intel 440MX, and the Victory66 are identical to the PIIX4 in I2C/SMBus support. -A few OSB4 southbridges are known to be misconfigured by the BIOS. In this -case, you have you use the fix_hstcfg module parameter. Do not use it -unless you know you have to, because in some cases it also breaks -configuration on southbridges that don't need it. +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://www2.lm-sensors.nu/~lm78/cvs/lm_sensors2/README.thinkpad |