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- .. 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
- ======================= =====================================================
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