DBCOOL(4) NetBSD Kernel Interfaces Manual DBCOOL(4)
NAME
dbcool, adm1027, adm1030, adt7463, adt7466, adt7467, adt7468, adt7473, adt7475, adt7476, adt7490 -- dbCool(tm) family of environmental monitors and fan controllers
SYNOPSIS
dbcool* at ki2c? dbcool* at iic? addr 0x2e
DESCRIPTION
The dbcool driver provides support for the Analog Devices dbCool environ- mental monitor chips to be used with the envsys(4) API. These chips support up to fourteen sensors. Not all of the following sensors are supported on all chips. Sensor Units Typical Use l_temp uK local chip temperature r1_temp uK CPU temperature r2_temp uK GPU temperature Vccp uV DC CPU Vcore Vcc uV DC Chip's supply voltage 2.5V uV DC 2.5V supply 5V uV DC 5V supply 12V uV DC 12V supply Vtt uV DC PECI ref. voltage (2.25V ref, ADT7490 only) Imon uV DC Current monitor (2.25V ref, ADT7490 only) AIN1 uV DC Analog In (2.25V ref, ADT7466 only) AIN2 uV DC Analog In (2.25V ref, ADT7466 only) fan1 RPM Chassis Fan fan2 RPM Chassis Fan fan3 RPM Chassis Fan fan4 RPM Chassis Fan Each temperature and voltage sensor has a programmable high- and low- limit; fan sensors have only a low-limit. The user can set the threshold values using sysctl(8) hw.dbcool0.l_temp.low_lim = 35 degrees C hw.dbcool0.l_temp.hi_lim = 75 degrees C hw.dbcool0.fan1.low_lim = 300 RPM hw.dbcool0.Vcc.low_lim = 2250 milliVolts hw.dbcool0.Vcc.hi_lim = 2750 milliVolts Temperature sensors also have Tmin, Trange, Thyst, and Ttherm sysctl(8) variables; these values are used by the fan speed controllers. All sysctl(8) variables associated with temperature sensors are in units of degC, since this is the unit which is programmed into the device reg- isters. Limit values for voltage sensors are in millivolts. The low limit value for fan sensors is measured in RPM; due to the manner in which fan speed is measured, the lowest possible value for a fan limit is 83 RPM. All members of the dbCool family support Pulse-Width Modulated (PWM) fan speed control based on temperature thresholds - the fan will spin up when one or more thermal sensors exceeds its configured Tmin value. The fan will go faster as the temperature rises, and will slow down as the tem- perature falls. If the temperature exceeds the sensor's Ttherm value, the THERM signal will be asserted, and if enabled the fan will run at full speed. The fan will be turned off when the sensor(s) that triggered it reports a temperature which is at least Thyst degrees below its Tmin threshold. Each fan controller is programmable using the following sysctl(8) vari- ables. hw.dbcool0.fan_ctl_0.behavior hw.dbcool0.fan_ctl_0.min_duty hw.dbcool0.fan_ctl_0.max_duty hw.dbcool0.fan_ctl_0.cur_duty The behavior variable controls the selection of temperature sensors asso- ciated with the fan controller. When the associated temperature sensor reaches its Tmin value, the fan controller starts the fan at its minimum duty cycle; when the associated temperature sensor reaches its Ttherm value and asserts the THERM signal (or if an external THERM signal is asserted), the fan controller sets the fan speed to a 100% duty cycle. Between these two settings, each temperature sensor is used to calculate a duty cycle linearly based on the slope defined by the temperature sen- sor's range variable. When the associated temperature falls at least Thyst degress below its Tmin value, the fan controller will turn off the fan. (On the ADM1030, the value for Thyst is fixed at 5 degrees C.) Valid values for the behavior variable are: local (not available on ADM1030) remote1 remote2 (not available on ADM1030) local+remote2 (not available on ADM1030) all-temps full-speed (not available on ADM1030) manual disabled When the behavior variable is set to ``manual'', the cur-duty variable becomes user-writeable and can be set to any value between 0 and 100 inclusive to control the fan's duty cycle manually. In all other behavior modes, the cur-duty variable is read-only and updates are ignored. The min-duty and max-duty variables define the range over which the fan controller will manage the fan's duty cycle. On the ADM1030, these val- ues are not separately controllable. The max-duty is fixed at 100%, and the cur-duty variable is used to specify the minimum duty cycle when the fan controller is running in automatic mode. Note that the duty-cycle value does not directly correspond to the fan's speed. That is, a 33% duty cycle does not mean that the fan runs at 33% of its maximum speed; in actuality, a 33% duty cycle drives the fan at a speed close to 50% of its maximum. Fan speed correlates approximately to the square root of the duty cycle.
EXAMPLES
The envstat(8) utility can be used to determine the sensors supported: Current CritMax CritMin CritCap Unit l_temp: 44.250 degC r1_temp: 41.250 degC r2_temp: N/A Vccp: 0.002 V Vcc: 3.351 V fan1: N/A fan2: N/A fan3: N/A fan4: N/A Using this information, the following commands in /etc/envsys.conf will set appropriate limits for CPU temperature and chip supply voltage, and powerd will be notified if the limits are exceeded: dbcool0 { sensor1 { warning-max = 60C; critical-max = 65C; } sensor4 { critical-min = 3.1; warning-min = 3.2; critical-max = 3.5; } } Alternatively, set the following commands in /etc/sysctl.conf to perform limit checking in the hardware: hw.dbcool0.r1_temp.hi_lim = 65 hw.dbcool0.Vcc.low_lim = 3200000 hw.dbcool0.Vcc.hi_lim = 3500000
SEE ALSO
envsys(4), envstat(8), powerd(8), sysctl(8)
HISTORY
The dbcool device appeared in NetBSD 5.0.
BUGS
Although the sensor limit registers can be programmed, there is currently no use of the dbCool chips' ability to generate an SMBus interrupt when the limits are exceeded. Limit checking is only performed when the sen- sor values are polled and refreshed. The ADT7466 chip, although officially a member of the dbCool family, is programmed quite differently. The fan controllers on this chip are not currently implemented. The PECI (Processor Environment Control Interface) temperature sensors and the associated PWM behavior modes on the ADT7490 are not currently supported. NetBSD 5.1.2 October 5, 2008 NetBSD 5.1.2
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