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1.. SPDX-License-Identifier: GPL-2.02 3Kernel driver drivetemp4=======================5 6 7References8----------9 10ANS T13/1699-D11Information technology - AT Attachment 8 - ATA/ATAPI Command Set (ATA8-ACS)12 13ANS Project T10/BSR INCITS 51314Information technology - SCSI Primary Commands - 4 (SPC-4)15 16ANS Project INCITS 55717Information technology - SCSI / ATA Translation - 5 (SAT-5)18 19 20Description21-----------22 23This driver supports reporting the temperature of disk and solid state24drives with temperature sensors.25 26If supported, it uses the ATA SCT Command Transport feature to read27the current drive temperature and, if available, temperature limits28as well as historic minimum and maximum temperatures. If SCT Command29Transport is not supported, the driver uses SMART attributes to read30the drive temperature.31 32 33Usage Note34----------35 36Reading the drive temperature may reset the spin down timer on some drives.37This has been observed with WD120EFAX drives, but may be seen with other38drives as well. The same behavior is observed if the 'hdtemp' or 'smartd'39tools are used to access the drive.40With the WD120EFAX drive, reading the drive temperature using the drivetemp41driver is still possible _after_ it transitioned to standby mode, and42reading the drive temperature in this mode will not cause the drive to43change its mode (meaning the drive will not spin up). It is unknown if other44drives experience similar behavior.45 46A known workaround for WD120EFAX drives is to read the drive temperature at47intervals larger than twice the spin-down time. Otherwise affected drives48will never spin down.49 50 51Sysfs entries52-------------53 54Only the temp1_input attribute is always available. Other attributes are55available only if reported by the drive. All temperatures are reported in56milli-degrees Celsius.57 58======================= =====================================================59temp1_input Current drive temperature60temp1_lcrit Minimum temperature limit. Operating the device below61 this temperature may cause physical damage to the62 device.63temp1_min Minimum recommended continuous operating limit64temp1_max Maximum recommended continuous operating temperature65temp1_crit Maximum temperature limit. Operating the device above66 this temperature may cause physical damage to the67 device.68temp1_lowest Minimum temperature seen this power cycle69temp1_highest Maximum temperature seen this power cycle70======================= =====================================================71