| .. SPDX-License-Identifier: GPL-2.0 |
| |
| Kernel driver drivetemp |
| ======================= |
| |
| |
| References |
| ---------- |
| |
| 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) |
| |
| |
| Description |
| ----------- |
| |
| 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. |
| |
| |
| Usage Note |
| ---------- |
| |
| Reading the drive temperature may reset the spin down timer on some drives. |
| This has been observed with WD120EFAX drives, but may be seen with other |
| drives as well. The same behavior is observed if the 'hdtemp' or 'smartd' |
| tools are used to access the drive. |
| With the WD120EFAX drive, reading the drive temperature using the drivetemp |
| driver is still possible _after_ it transitioned to standby mode, and |
| reading the drive temperature in this mode will not cause the drive to |
| change its mode (meaning the drive will not spin up). It is unknown if other |
| drives experience similar behavior. |
| |
| A known workaround for WD120EFAX drives is to read the drive temperature at |
| intervals larger than twice the spin-down time. Otherwise affected drives |
| will never spin down. |
| |
| |
| 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 |
| ======================= ===================================================== |
