Kernel driver minisforum-um780xtx

Supported systems:

  • Minisforum UM780 XTX

    • DMI product name: Venus series

    • Mainboard: F7BSD, revision 1.1

    • BIOS version: 1.06

Author: Sebastián Peyrott <speyrott@gmail.com>

Description

This driver exposes hardware monitoring and fan-control data cached by the IT5571E embedded controller. It uses the ACPI EC transport and only binds to the exact system and firmware identity listed above.

The two temperature channels are the values used by the EC’s fan-control loops. Their physical sensor placement is not known. The CPU channel is the filtered AMD SB-TSI temperature, while the system channel is an external thermistor input.

The fan tachometers are read through OEM EC commands. Since each byte is returned by a separate command, the driver uses a high-low-high sequence and retries if the high byte changes.

Sysfs entries

temp1_input

CPU-fan control temperature

temp2_input

System-fan control temperature

fan1_input

CPU fan speed in RPM

fan2_input

System fan speed in RPM

pwm1_enable

CPU profile: 2 is OEM B1, 3 is OEM B2

pwm2_auto_point1_temp

Off-to-low system-fan transition temperature

pwm2_auto_point2_temp

Low-to-high system-fan transition temperature

CPU fan profiles

Values 2 and 3 of pwm1_enable select the two complete automatic profiles implemented by the firmware. Writing either value reloads the whole CPU fan curve, including firmware state which is not visible through the ACPI EC window. Other values are rejected.

System fan thresholds

The two writable system-fan temperatures are rounded to whole degrees Celsius and clamped to preserve strict ordering between both visible thresholds and the firmware’s internal third threshold. The third threshold does not select a new PWM target and is therefore not exposed as another auto point.

Resume state preservation

Fan settings are held in EC RAM. On the supported firmware, initialization during s2idle resume reloads the factory system-fan curve. The driver retains the last coherent CPU profile and system-fan thresholds selected through its interface and restores them synchronously at resume.