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VIAPM(4) Device Drivers Manual VIAPM(4)

viapmVIA SMBus controller and VIA VT82C686A/VT8231 hardware monitor

viapm* at pci?
iic* at viapm?

The viapm driver provides support for the bus control and power management component of the VIA VT82C596, VT82C596B, VT82C686A, VT8231, VT8233, VT8233A, VT8235, VT8237, VT8237A, VT8237S, VT8251, CX700, VX800, VX855 and VX900 South Bridges. Only the SMBus host interface is supported and can be used with the iic(4) framework.

The viapm driver provides support for the hardware monitor in the VIA VT82C686A and VT8231 South Bridges. The hardware monitor is used with the sysctl(8) interface.

The device has 10 sensors:

uK CPU temperature
uK System temperature
uK Unknown
RPM CPU fan
RPM System fan
uV DC CPU core voltage (2.0V)
uV DC North Bridge core voltage (2.5V)
uV DC Internal core voltage (3.3V)
uV DC +5V
uV DC +12V

Sensor data is updated every 1.5 seconds.

iic(4), intro(4), pci(4), sensorsd(8), sysctl(8)

The viapm driver first appeared in OpenBSD 3.9.

The viaenv driver first appeared in NetBSD 1.5. OpenBSD support was added in OpenBSD 3.4.

The viapm driver was written by Mark Kettenis <kettenis@openbsd.org>.

The viaenv driver was written by Johan Danielsson and ported to OpenBSD 3.4 by Alexander Yurchenko <grange@openbsd.org>. It was merged with viapm in OpenBSD 5.0.

The driver doesn't support commands with a data buffer size of more than 2 bytes.

Interrupt support is unimplemented, as is support for setting values.

July 5, 2018 OpenBSD-6.7