| Guenter Roeck | 5b46903 | 2019-11-28 21:34:40 -0800 | [diff] [blame] | 1 | .. SPDX-License-Identifier: GPL-2.0 |
| 2 | |
| 3 | Kernel driver drivetemp |
| 4 | ======================= |
| 5 | |
| 6 | |
| 7 | References |
| 8 | ---------- |
| 9 | |
| 10 | ANS T13/1699-D |
| 11 | Information technology - AT Attachment 8 - ATA/ATAPI Command Set (ATA8-ACS) |
| 12 | |
| 13 | ANS Project T10/BSR INCITS 513 |
| 14 | Information technology - SCSI Primary Commands - 4 (SPC-4) |
| 15 | |
| 16 | ANS Project INCITS 557 |
| 17 | Information technology - SCSI / ATA Translation - 5 (SAT-5) |
| 18 | |
| 19 | |
| 20 | Description |
| 21 | ----------- |
| 22 | |
| 23 | This driver supports reporting the temperature of disk and solid state |
| 24 | drives with temperature sensors. |
| 25 | |
| 26 | If supported, it uses the ATA SCT Command Transport feature to read |
| 27 | the current drive temperature and, if available, temperature limits |
| 28 | as well as historic minimum and maximum temperatures. If SCT Command |
| 29 | Transport is not supported, the driver uses SMART attributes to read |
| 30 | the drive temperature. |
| 31 | |
| 32 | |
| Guenter Roeck | e403583 | 2020-08-08 18:07:10 -0700 | [diff] [blame] | 33 | Usage Note |
| 34 | ---------- |
| 35 | |
| 36 | Reading the drive temperature may reset the spin down timer on some drives. |
| 37 | This has been observed with WD120EFAX drives, but may be seen with other |
| 38 | drives as well. The same behavior is observed if the 'hdtemp' or 'smartd' |
| 39 | tools are used to access the drive. |
| 40 | With the WD120EFAX drive, reading the drive temperature using the drivetemp |
| 41 | driver is still possible _after_ it transitioned to standby mode, and |
| 42 | reading the drive temperature in this mode will not cause the drive to |
| 43 | change its mode (meaning the drive will not spin up). It is unknown if other |
| 44 | drives experience similar behavior. |
| 45 | |
| 46 | A known workaround for WD120EFAX drives is to read the drive temperature at |
| 47 | intervals larger than twice the spin-down time. Otherwise affected drives |
| 48 | will never spin down. |
| 49 | |
| 50 | |
| Guenter Roeck | 5b46903 | 2019-11-28 21:34:40 -0800 | [diff] [blame] | 51 | Sysfs entries |
| 52 | ------------- |
| 53 | |
| 54 | Only the temp1_input attribute is always available. Other attributes are |
| 55 | available only if reported by the drive. All temperatures are reported in |
| 56 | milli-degrees Celsius. |
| 57 | |
| 58 | ======================= ===================================================== |
| 59 | temp1_input Current drive temperature |
| 60 | temp1_lcrit Minimum temperature limit. Operating the device below |
| 61 | this temperature may cause physical damage to the |
| 62 | device. |
| 63 | temp1_min Minimum recommended continuous operating limit |
| 64 | temp1_max Maximum recommended continuous operating temperature |
| 65 | temp1_crit Maximum temperature limit. Operating the device above |
| 66 | this temperature may cause physical damage to the |
| 67 | device. |
| 68 | temp1_lowest Minimum temperature seen this power cycle |
| 69 | temp1_highest Maximum temperature seen this power cycle |
| 70 | ======================= ===================================================== |