mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-11-25 04:20:53 +07:00
408 lines
12 KiB
Plaintext
408 lines
12 KiB
Plaintext
Naming and data format standards for sysfs files
|
|
------------------------------------------------
|
|
|
|
The libsensors library offers an interface to the raw sensors data
|
|
through the sysfs interface. See libsensors documentation and source for
|
|
further information. As of writing this document, libsensors
|
|
(from lm_sensors 2.8.3) is heavily chip-dependent. Adding or updating
|
|
support for any given chip requires modifying the library's code.
|
|
This is because libsensors was written for the procfs interface
|
|
older kernel modules were using, which wasn't standardized enough.
|
|
Recent versions of libsensors (from lm_sensors 2.8.2 and later) have
|
|
support for the sysfs interface, though.
|
|
|
|
The new sysfs interface was designed to be as chip-independent as
|
|
possible.
|
|
|
|
Note that motherboards vary widely in the connections to sensor chips.
|
|
There is no standard that ensures, for example, that the second
|
|
temperature sensor is connected to the CPU, or that the second fan is on
|
|
the CPU. Also, some values reported by the chips need some computation
|
|
before they make full sense. For example, most chips can only measure
|
|
voltages between 0 and +4V. Other voltages are scaled back into that
|
|
range using external resistors. Since the values of these resistors
|
|
can change from motherboard to motherboard, the conversions cannot be
|
|
hard coded into the driver and have to be done in user space.
|
|
|
|
For this reason, even if we aim at a chip-independent libsensors, it will
|
|
still require a configuration file (e.g. /etc/sensors.conf) for proper
|
|
values conversion, labeling of inputs and hiding of unused inputs.
|
|
|
|
An alternative method that some programs use is to access the sysfs
|
|
files directly. This document briefly describes the standards that the
|
|
drivers follow, so that an application program can scan for entries and
|
|
access this data in a simple and consistent way. That said, such programs
|
|
will have to implement conversion, labeling and hiding of inputs. For
|
|
this reason, it is still not recommended to bypass the library.
|
|
|
|
If you are developing a userspace application please send us feedback on
|
|
this standard.
|
|
|
|
Note that this standard isn't completely established yet, so it is subject
|
|
to changes. If you are writing a new hardware monitoring driver those
|
|
features can't seem to fit in this interface, please contact us with your
|
|
extension proposal. Keep in mind that backward compatibility must be
|
|
preserved.
|
|
|
|
Each chip gets its own directory in the sysfs /sys/devices tree. To
|
|
find all sensor chips, it is easier to follow the device symlinks from
|
|
/sys/class/hwmon/hwmon*.
|
|
|
|
All sysfs values are fixed point numbers.
|
|
|
|
There is only one value per file, unlike the older /proc specification.
|
|
The common scheme for files naming is: <type><number>_<item>. Usual
|
|
types for sensor chips are "in" (voltage), "temp" (temperature) and
|
|
"fan" (fan). Usual items are "input" (measured value), "max" (high
|
|
threshold, "min" (low threshold). Numbering usually starts from 1,
|
|
except for voltages which start from 0 (because most data sheets use
|
|
this). A number is always used for elements that can be present more
|
|
than once, even if there is a single element of the given type on the
|
|
specific chip. Other files do not refer to a specific element, so
|
|
they have a simple name, and no number.
|
|
|
|
Alarms are direct indications read from the chips. The drivers do NOT
|
|
make comparisons of readings to thresholds. This allows violations
|
|
between readings to be caught and alarmed. The exact definition of an
|
|
alarm (for example, whether a threshold must be met or must be exceeded
|
|
to cause an alarm) is chip-dependent.
|
|
|
|
|
|
-------------------------------------------------------------------------
|
|
|
|
[0-*] denotes any positive number starting from 0
|
|
[1-*] denotes any positive number starting from 1
|
|
RO read only value
|
|
RW read/write value
|
|
|
|
Read/write values may be read-only for some chips, depending on the
|
|
hardware implementation.
|
|
|
|
All entries are optional, and should only be created in a given driver
|
|
if the chip has the feature.
|
|
|
|
************
|
|
* Voltages *
|
|
************
|
|
|
|
in[0-*]_min Voltage min value.
|
|
Unit: millivolt
|
|
RW
|
|
|
|
in[0-*]_max Voltage max value.
|
|
Unit: millivolt
|
|
RW
|
|
|
|
in[0-*]_input Voltage input value.
|
|
Unit: millivolt
|
|
RO
|
|
Voltage measured on the chip pin.
|
|
Actual voltage depends on the scaling resistors on the
|
|
motherboard, as recommended in the chip datasheet.
|
|
This varies by chip and by motherboard.
|
|
Because of this variation, values are generally NOT scaled
|
|
by the chip driver, and must be done by the application.
|
|
However, some drivers (notably lm87 and via686a)
|
|
do scale, because of internal resistors built into a chip.
|
|
These drivers will output the actual voltage.
|
|
|
|
Typical usage:
|
|
in0_* CPU #1 voltage (not scaled)
|
|
in1_* CPU #2 voltage (not scaled)
|
|
in2_* 3.3V nominal (not scaled)
|
|
in3_* 5.0V nominal (scaled)
|
|
in4_* 12.0V nominal (scaled)
|
|
in5_* -12.0V nominal (scaled)
|
|
in6_* -5.0V nominal (scaled)
|
|
in7_* varies
|
|
in8_* varies
|
|
|
|
cpu[0-*]_vid CPU core reference voltage.
|
|
Unit: millivolt
|
|
RO
|
|
Not always correct.
|
|
|
|
vrm Voltage Regulator Module version number.
|
|
RW (but changing it should no more be necessary)
|
|
Originally the VRM standard version multiplied by 10, but now
|
|
an arbitrary number, as not all standards have a version
|
|
number.
|
|
Affects the way the driver calculates the CPU core reference
|
|
voltage from the vid pins.
|
|
|
|
Also see the Alarms section for status flags associated with voltages.
|
|
|
|
|
|
********
|
|
* Fans *
|
|
********
|
|
|
|
fan[1-*]_min Fan minimum value
|
|
Unit: revolution/min (RPM)
|
|
RW
|
|
|
|
fan[1-*]_input Fan input value.
|
|
Unit: revolution/min (RPM)
|
|
RO
|
|
|
|
fan[1-*]_div Fan divisor.
|
|
Integer value in powers of two (1, 2, 4, 8, 16, 32, 64, 128).
|
|
RW
|
|
Some chips only support values 1, 2, 4 and 8.
|
|
Note that this is actually an internal clock divisor, which
|
|
affects the measurable speed range, not the read value.
|
|
|
|
fan[1-*]_target
|
|
Desired fan speed
|
|
Unit: revolution/min (RPM)
|
|
RW
|
|
Only makes sense if the chip supports closed-loop fan speed
|
|
control based on the measured fan speed.
|
|
|
|
Also see the Alarms section for status flags associated with fans.
|
|
|
|
|
|
*******
|
|
* PWM *
|
|
*******
|
|
|
|
pwm[1-*] Pulse width modulation fan control.
|
|
Integer value in the range 0 to 255
|
|
RW
|
|
255 is max or 100%.
|
|
|
|
pwm[1-*]_enable
|
|
Switch PWM on and off.
|
|
Not always present even if pwmN is.
|
|
0: turn off
|
|
1: turn on in manual mode
|
|
2+: turn on in automatic mode
|
|
Check individual chip documentation files for automatic mode
|
|
details.
|
|
RW
|
|
|
|
pwm[1-*]_mode 0: DC mode (direct current)
|
|
1: PWM mode (pulse-width modulation)
|
|
RW
|
|
|
|
pwm[1-*]_freq Base PWM frequency in Hz.
|
|
Only possibly available when pwmN_mode is PWM, but not always
|
|
present even then.
|
|
RW
|
|
|
|
pwm[1-*]_auto_channels_temp
|
|
Select which temperature channels affect this PWM output in
|
|
auto mode. Bitfield, 1 is temp1, 2 is temp2, 4 is temp3 etc...
|
|
Which values are possible depend on the chip used.
|
|
RW
|
|
|
|
pwm[1-*]_auto_point[1-*]_pwm
|
|
pwm[1-*]_auto_point[1-*]_temp
|
|
pwm[1-*]_auto_point[1-*]_temp_hyst
|
|
Define the PWM vs temperature curve. Number of trip points is
|
|
chip-dependent. Use this for chips which associate trip points
|
|
to PWM output channels.
|
|
RW
|
|
|
|
OR
|
|
|
|
temp[1-*]_auto_point[1-*]_pwm
|
|
temp[1-*]_auto_point[1-*]_temp
|
|
temp[1-*]_auto_point[1-*]_temp_hyst
|
|
Define the PWM vs temperature curve. Number of trip points is
|
|
chip-dependent. Use this for chips which associate trip points
|
|
to temperature channels.
|
|
RW
|
|
|
|
|
|
****************
|
|
* Temperatures *
|
|
****************
|
|
|
|
temp[1-*]_type Sensor type selection.
|
|
Integers 1 to 6 or thermistor Beta value (typically 3435)
|
|
RW
|
|
1: PII/Celeron Diode
|
|
2: 3904 transistor
|
|
3: thermal diode
|
|
4: thermistor (default/unknown Beta)
|
|
5: AMD AMDSI
|
|
6: Intel PECI
|
|
Not all types are supported by all chips
|
|
|
|
temp[1-*]_max Temperature max value.
|
|
Unit: millidegree Celsius (or millivolt, see below)
|
|
RW
|
|
|
|
temp[1-*]_min Temperature min value.
|
|
Unit: millidegree Celsius
|
|
RW
|
|
|
|
temp[1-*]_max_hyst
|
|
Temperature hysteresis value for max limit.
|
|
Unit: millidegree Celsius
|
|
Must be reported as an absolute temperature, NOT a delta
|
|
from the max value.
|
|
RW
|
|
|
|
temp[1-*]_input Temperature input value.
|
|
Unit: millidegree Celsius
|
|
RO
|
|
|
|
temp[1-*]_crit Temperature critical value, typically greater than
|
|
corresponding temp_max values.
|
|
Unit: millidegree Celsius
|
|
RW
|
|
|
|
temp[1-*]_crit_hyst
|
|
Temperature hysteresis value for critical limit.
|
|
Unit: millidegree Celsius
|
|
Must be reported as an absolute temperature, NOT a delta
|
|
from the critical value.
|
|
RW
|
|
|
|
temp[1-4]_offset
|
|
Temperature offset which is added to the temperature reading
|
|
by the chip.
|
|
Unit: millidegree Celsius
|
|
Read/Write value.
|
|
|
|
If there are multiple temperature sensors, temp1_* is
|
|
generally the sensor inside the chip itself,
|
|
reported as "motherboard temperature". temp2_* to
|
|
temp4_* are generally sensors external to the chip
|
|
itself, for example the thermal diode inside the CPU or
|
|
a thermistor nearby.
|
|
|
|
Some chips measure temperature using external thermistors and an ADC, and
|
|
report the temperature measurement as a voltage. Converting this voltage
|
|
back to a temperature (or the other way around for limits) requires
|
|
mathematical functions not available in the kernel, so the conversion
|
|
must occur in user space. For these chips, all temp* files described
|
|
above should contain values expressed in millivolt instead of millidegree
|
|
Celsius. In other words, such temperature channels are handled as voltage
|
|
channels by the driver.
|
|
|
|
Also see the Alarms section for status flags associated with temperatures.
|
|
|
|
|
|
************
|
|
* Currents *
|
|
************
|
|
|
|
Note that no known chip provides current measurements as of writing,
|
|
so this part is theoretical, so to say.
|
|
|
|
curr[1-*]_max Current max value
|
|
Unit: milliampere
|
|
RW
|
|
|
|
curr[1-*]_min Current min value.
|
|
Unit: milliampere
|
|
RW
|
|
|
|
curr[1-*]_input Current input value
|
|
Unit: milliampere
|
|
RO
|
|
|
|
|
|
**********
|
|
* Alarms *
|
|
**********
|
|
|
|
Each channel or limit may have an associated alarm file, containing a
|
|
boolean value. 1 means than an alarm condition exists, 0 means no alarm.
|
|
|
|
Usually a given chip will either use channel-related alarms, or
|
|
limit-related alarms, not both. The driver should just reflect the hardware
|
|
implementation.
|
|
|
|
in[0-*]_alarm
|
|
fan[1-*]_alarm
|
|
temp[1-*]_alarm
|
|
Channel alarm
|
|
0: no alarm
|
|
1: alarm
|
|
RO
|
|
|
|
OR
|
|
|
|
in[0-*]_min_alarm
|
|
in[0-*]_max_alarm
|
|
fan[1-*]_min_alarm
|
|
temp[1-*]_min_alarm
|
|
temp[1-*]_max_alarm
|
|
temp[1-*]_crit_alarm
|
|
Limit alarm
|
|
0: no alarm
|
|
1: alarm
|
|
RO
|
|
|
|
Each input channel may have an associated fault file. This can be used
|
|
to notify open diodes, unconnected fans etc. where the hardware
|
|
supports it. When this boolean has value 1, the measurement for that
|
|
channel should not be trusted.
|
|
|
|
in[0-*]_input_fault
|
|
fan[1-*]_input_fault
|
|
temp[1-*]_input_fault
|
|
Input fault condition
|
|
0: no fault occured
|
|
1: fault condition
|
|
RO
|
|
|
|
Some chips also offer the possibility to get beeped when an alarm occurs:
|
|
|
|
beep_enable Master beep enable
|
|
0: no beeps
|
|
1: beeps
|
|
RW
|
|
|
|
in[0-*]_beep
|
|
fan[1-*]_beep
|
|
temp[1-*]_beep
|
|
Channel beep
|
|
0: disable
|
|
1: enable
|
|
RW
|
|
|
|
In theory, a chip could provide per-limit beep masking, but no such chip
|
|
was seen so far.
|
|
|
|
Old drivers provided a different, non-standard interface to alarms and
|
|
beeps. These interface files are deprecated, but will be kept around
|
|
for compatibility reasons:
|
|
|
|
alarms Alarm bitmask.
|
|
RO
|
|
Integer representation of one to four bytes.
|
|
A '1' bit means an alarm.
|
|
Chips should be programmed for 'comparator' mode so that
|
|
the alarm will 'come back' after you read the register
|
|
if it is still valid.
|
|
Generally a direct representation of a chip's internal
|
|
alarm registers; there is no standard for the position
|
|
of individual bits. For this reason, the use of this
|
|
interface file for new drivers is discouraged. Use
|
|
individual *_alarm and *_fault files instead.
|
|
Bits are defined in kernel/include/sensors.h.
|
|
|
|
beep_mask Bitmask for beep.
|
|
Same format as 'alarms' with the same bit locations,
|
|
use discouraged for the same reason. Use individual
|
|
*_beep files instead.
|
|
RW
|
|
|
|
|
|
*********
|
|
* Other *
|
|
*********
|
|
|
|
eeprom Raw EEPROM data in binary form.
|
|
RO
|
|
|
|
pec Enable or disable PEC (SMBus only)
|
|
0: disable
|
|
1: enable
|
|
RW
|