projects / linux-2.6-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 5b46903d GR |
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 | ||
| e4035839 GR |
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 | ||
| 5b46903d GR |
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 | ======================= ===================================================== |