0001 .. SPDX-License-Identifier: GPL-2.0
0002
0003 Kernel driver drivetemp
0004 =======================
0005
0006
0007 References
0008 ----------
0009
0010 ANS T13/1699-D
0011 Information technology - AT Attachment 8 - ATA/ATAPI Command Set (ATA8-ACS)
0012
0013 ANS Project T10/BSR INCITS 513
0014 Information technology - SCSI Primary Commands - 4 (SPC-4)
0015
0016 ANS Project INCITS 557
0017 Information technology - SCSI / ATA Translation - 5 (SAT-5)
0018
0019
0020 Description
0021 -----------
0022
0023 This driver supports reporting the temperature of disk and solid state
0024 drives with temperature sensors.
0025
0026 If supported, it uses the ATA SCT Command Transport feature to read
0027 the current drive temperature and, if available, temperature limits
0028 as well as historic minimum and maximum temperatures. If SCT Command
0029 Transport is not supported, the driver uses SMART attributes to read
0030 the drive temperature.
0031
0032
0033 Usage Note
0034 ----------
0035
0036 Reading the drive temperature may reset the spin down timer on some drives.
0037 This has been observed with WD120EFAX drives, but may be seen with other
0038 drives as well. The same behavior is observed if the 'hdtemp' or 'smartd'
0039 tools are used to access the drive.
0040 With the WD120EFAX drive, reading the drive temperature using the drivetemp
0041 driver is still possible _after_ it transitioned to standby mode, and
0042 reading the drive temperature in this mode will not cause the drive to
0043 change its mode (meaning the drive will not spin up). It is unknown if other
0044 drives experience similar behavior.
0045
0046 A known workaround for WD120EFAX drives is to read the drive temperature at
0047 intervals larger than twice the spin-down time. Otherwise affected drives
0048 will never spin down.
0049
0050
0051 Sysfs entries
0052 -------------
0053
0054 Only the temp1_input attribute is always available. Other attributes are
0055 available only if reported by the drive. All temperatures are reported in
0056 milli-degrees Celsius.
0057
0058 ======================= =====================================================
0059 temp1_input Current drive temperature
0060 temp1_lcrit Minimum temperature limit. Operating the device below
0061 this temperature may cause physical damage to the
0062 device.
0063 temp1_min Minimum recommended continuous operating limit
0064 temp1_max Maximum recommended continuous operating temperature
0065 temp1_crit Maximum temperature limit. Operating the device above
0066 this temperature may cause physical damage to the
0067 device.
0068 temp1_lowest Minimum temperature seen this power cycle
0069 temp1_highest Maximum temperature seen this power cycle
0070 ======================= =====================================================
