Workarounds for Piix4_smbus ****host SMBus Controller not enabled

SMBus

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the difference between SMBus and I²c

SMBus is the abbreviation for System Management Bus, which was proposed by Intel in 1995 for low-rate communication in mobile PC and desktop PC systems.　　It mainly wants to control the device on the motherboard and collect the information by means of a cheap and powerful bus (consisting of two lines).　　SMBus provides a control bus for tasks such as system and power management, using a SMBus system that sends and receives messages between devices through SMBus, rather than using separate control lines, which saves the number of pins on the device.　　Using SMBus, the device can also provide information about its production, tell the system its model number, part number, etc., save its state for a pending event, report different categories of errors, receive control parameters, and return its status.　　The SMBus device has the first 3 layers in the existing 7-layer OSI network model, namely the physical layer, the data link layer, and the network layer. The original purpose of the SMBus is to define the communication link between the Smart battery, the rechargeable battery, and the microcontroller that communicates with other systems.　　SMBus is also used to connect a variety of devices, including power-related equipment, system sensors, EEPROM communication devices and more. The SMBus is best for laptops, detects individual component states, and updates hardware setup pins (Pull-high or pull-low). For example, the non-existent DIMM clock is turned off, or the battery low voltage status is detected. The SMBus data transfer rate is only 100kbit/s; This allows a single host to communicate with the CPU and multiple master and slave drives and send and receive data.　　The SMBus can also be used on motherboards with jumper-free designs. SMBus is the abbreviation of System Management Bus, which is translated into Systems management bus, SMBus is a second-line serial bus, the first edition of 1996 specification began commercial. It is mostly based on the I²C bus specification. Like I²c, SMBus does not need to increase the amount of the foot, the main purpose of this bus is to add new features, but only work at 100kHz and specifically for smart battery management applications. It works in master/slave mode: The main device provides a clock, provides a starting bit when it initiates a transmission, provides a stop bit when it terminates a transmission, and a unique 7-or 10-bit slave address from the device

the difference between SMBus and I²c

There are some differences in timing characteristics between the SMBus and the I²c bus. First, the SMBus requires a certain amount of data retention time, while the I²C bus extends the data retention time from within. The SMBus has a timeout function, so when the SCL is too low for more than a few MS, the slave device resets the ongoing communication. Instead, I²C uses a hardware reset. The SMBus has an alert response address (ARA), so when an interrupt is generated from the device, it does not immediately clear the interrupt, but remains until it receives a ARA with its address sent by the main device. SMBus only works from 10kHz to up to 100kHz. Minimum operating frequency 10kHz is determined by the SMBus timeout function

CentOS 6.0 starts with the following prompts:

1. (1) Workaround for Piix4_smbus ****host SMBus Controller not enabled

   [[Email protected] on/tmp/] #lsmod |grep i2c_piix4 i2c_piix422401  0I2c_core63151  3Drm,i2c_piix4,drm_kms_helper[[email protected]-nginx- on/tmp/] #cat/etc/modprobe.d/blacklist.conf Cat:/etc/modprobe.d/blacklist.conf:No such file or Directory[[email protected]-nginx- on/tmp/] #echo"blacklist i2c_piix4">/etc/modprobe.d/blacklist.conf [[email protected]-nginx- on/tmp/] #reboot

3. No more prompts after reboot!

Workaround for Piix4_smbus ****host SMBus Controller not enabled