ISMT(4D) Devices ISMT(4D)

ismtIntel SMBus Message Transport driver

The ismt driver is an SMBus 3.0 controller with I2C support that is present on various Intel Atom and Xeon-D platforms.

The ismt driver is part of the system's I2C framework and is accessible through common tools such as i2cadm(8). The controller ssupports a mixture of SMBus 2.0 and 3.0 features, but is still limited to a 32-byte block buffer and does not support the SMBus 32-bit and 64-bit protocols directly in its SMBus operation. Unlike pchsmbus(4D), ismt also has support for I2C based operations and can use up to a 240-byte buffer for them. The ismt driver currently only has read-only properties. While the controller supports a variable bus frequency, these are supposed to only be set by fuses by the platform implementor.

/kernel/drv/amd64/ismt
Device driver (x86)

pchsmbus(4D), i2cadm(8)

October 4, 2025 OmniOS