path: root/Documentation/hwmon
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authorGuenter Roeck <linux@roeck-us.net>2019-11-28 21:34:40 -0800
committerGuenter Roeck <linux@roeck-us.net>2020-01-23 13:15:10 -0800
commit5b46903d8bf372e563bf2150d46b87fff197a109 (patch)
tree552d22394abb057b9731ffb492a75ad77bef69de /Documentation/hwmon
parenthwmon: (pmbus/ibm-cffps) Fix the LED behavior when turned off (diff)
hwmon: Driver for disk and solid state drives with temperature sensors
Reading the temperature of ATA drives has been supported for years by userspace tools such as smarttools or hddtemp. The downside of such tools is that they need to run with super-user privilege, that the temperatures are not reported by standard tools such as 'sensors' or 'libsensors', and that drive temperatures are not available for use in the kernel's thermal subsystem. This driver solves this problem by adding support for reading the temperature of ATA drives from the kernel using the hwmon API and by adding a temperature zone for each drive. With this driver, the hard disk temperature can be read using the unprivileged 'sensors' application: $ sensors drivetemp-scsi-1-0 drivetemp-scsi-1-0 Adapter: SCSI adapter temp1: +23.0°C or directly from sysfs: $ grep . /sys/class/hwmon/hwmon9/{name,temp1_input} /sys/class/hwmon/hwmon9/name:drivetemp /sys/class/hwmon/hwmon9/temp1_input:23000 If the drive supports SCT transport and reports temperature limits, those are reported as well. drivetemp-scsi-0-0 Adapter: SCSI adapter temp1: +27.0°C (low = +0.0°C, high = +60.0°C) (crit low = -41.0°C, crit = +85.0°C) (lowest = +23.0°C, highest = +34.0°C) The driver attempts to use SCT Command Transport to read the drive temperature. If the SCT Command Transport feature set is not available, or if it does not report the drive temperature, drive temperatures may be readable through SMART attributes. Since SMART attributes are not well defined, this method is only used as fallback mechanism. Cc: Chris Healy <cphealy@gmail.com> Cc: Linus Walleij <linus.walleij@linaro.org> Cc: Martin K. Petersen <martin.petersen@oracle.com> Cc: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Tested-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Diffstat (limited to 'Documentation/hwmon')
2 files changed, 53 insertions, 0 deletions
diff --git a/Documentation/hwmon/drivetemp.rst b/Documentation/hwmon/drivetemp.rst
new file mode 100644
index 000000000000..2d37d049247f
--- /dev/null
+++ b/Documentation/hwmon/drivetemp.rst
@@ -0,0 +1,52 @@
+.. SPDX-License-Identifier: GPL-2.0
+Kernel driver drivetemp
+ANS T13/1699-D
+Information technology - AT Attachment 8 - ATA/ATAPI Command Set (ATA8-ACS)
+ANS Project T10/BSR INCITS 513
+Information technology - SCSI Primary Commands - 4 (SPC-4)
+ANS Project INCITS 557
+Information technology - SCSI / ATA Translation - 5 (SAT-5)
+This driver supports reporting the temperature of disk and solid state
+drives with temperature sensors.
+If supported, it uses the ATA SCT Command Transport feature to read
+the current drive temperature and, if available, temperature limits
+as well as historic minimum and maximum temperatures. If SCT Command
+Transport is not supported, the driver uses SMART attributes to read
+the drive temperature.
+Sysfs entries
+Only the temp1_input attribute is always available. Other attributes are
+available only if reported by the drive. All temperatures are reported in
+milli-degrees Celsius.
+======================= =====================================================
+temp1_input Current drive temperature
+temp1_lcrit Minimum temperature limit. Operating the device below
+ this temperature may cause physical damage to the
+ device.
+temp1_min Minimum recommended continuous operating limit
+temp1_max Maximum recommended continuous operating temperature
+temp1_crit Maximum temperature limit. Operating the device above
+ this temperature may cause physical damage to the
+ device.
+temp1_lowest Minimum temperature seen this power cycle
+temp1_highest Maximum temperature seen this power cycle
+======================= =====================================================
diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index 6f88af43eed6..682ef4dda89c 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -47,6 +47,7 @@ Hardware Monitoring Kernel Drivers
+ drivetemp