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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 | ======================= ===================================================== |