1.. SPDX-License-Identifier: GPL-2.0 2 3Kernel driver drivetemp 4======================= 5 6 7References 8---------- 9 10ANS T13/1699-D 11Information technology - AT Attachment 8 - ATA/ATAPI Command Set (ATA8-ACS) 12 13ANS Project T10/BSR INCITS 513 14Information technology - SCSI Primary Commands - 4 (SPC-4) 15 16ANS Project INCITS 557 17Information technology - SCSI / ATA Translation - 5 (SAT-5) 18 19 20Description 21----------- 22 23This driver supports reporting the temperature of disk and solid state 24drives with temperature sensors. 25 26If supported, it uses the ATA SCT Command Transport feature to read 27the current drive temperature and, if available, temperature limits 28as well as historic minimum and maximum temperatures. If SCT Command 29Transport is not supported, the driver uses SMART attributes to read 30the drive temperature. 31 32 33Usage Note 34---------- 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 other 38drives 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 drivetemp 41driver is still possible _after_ it transitioned to standby mode, and 42reading the drive temperature in this mode will not cause the drive to 43change its mode (meaning the drive will not spin up). It is unknown if other 44drives experience similar behavior. 45 46A known workaround for WD120EFAX drives is to read the drive temperature at 47intervals larger than twice the spin-down time. Otherwise affected drives 48will never spin down. 49 50 51Sysfs entries 52------------- 53 54Only the temp1_input attribute is always available. Other attributes are 55available only if reported by the drive. All temperatures are reported in 56milli-degrees Celsius. 57 58======================= ===================================================== 59temp1_input Current drive temperature 60temp1_lcrit Minimum temperature limit. Operating the device below 61 this temperature may cause physical damage to the 62 device. 63temp1_min Minimum recommended continuous operating limit 64temp1_max Maximum recommended continuous operating temperature 65temp1_crit Maximum temperature limit. Operating the device above 66 this temperature may cause physical damage to the 67 device. 68temp1_lowest Minimum temperature seen this power cycle 69temp1_highest Maximum temperature seen this power cycle 70======================= ===================================================== 71