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1What: /sys/block/*/device/sw_activity
2Date: Jun, 2008
3KernelVersion: v2.6.27
4Contact: linux-ide@vger.kernel.org
5Description:
6 (RW) Used by drivers which support software controlled activity
7 LEDs.
8
9 It has the following valid values:
10
11 == ========================================================
12 0 OFF - the LED is not activated on activity
13 1 BLINK_ON - the LED blinks on every 10ms when activity is
14 detected.
15 2 BLINK_OFF - the LED is on when idle, and blinks off
16 every 10ms when activity is detected.
17 == ========================================================
18
19 Note that the user must turn sw_activity OFF it they wish to
20 control the activity LED via the em_message file.
21
22
23What: /sys/block/*/device/unload_heads
24Date: Sep, 2008
25KernelVersion: v2.6.28
26Contact: linux-ide@vger.kernel.org
27Description:
28 (RW) Hard disk shock protection
29
30 Writing an integer value to this file will take the heads of the
31 respective drive off the platter and block all I/O operations
32 for the specified number of milliseconds.
33
34 - If the device does not support the unload heads feature,
35 access is denied with -EOPNOTSUPP.
36 - The maximal value accepted for a timeout is 30000
37 milliseconds.
38 - A previously set timeout can be cancelled and disk can resume
39 normal operation immediately by specifying a timeout of 0.
40 - Some hard drives only comply with an earlier version of the
41 ATA standard, but support the unload feature nonetheless.
42 There is no safe way Linux can detect these devices, so this
43 is not enabled by default. If it is known that your device
44 does support the unload feature, then you can tell the kernel
45 to enable it by writing -1. It can be disabled again by
46 writing -2.
47 - Values below -2 are rejected with -EINVAL
48
49 For more information, see
50 Documentation/admin-guide/laptops/disk-shock-protection.rst
51
52
53What: /sys/block/*/device/ncq_prio_enable
54Date: Oct, 2016
55KernelVersion: v4.10
56Contact: linux-ide@vger.kernel.org
57Description:
58 (RW) Write to the file to turn on or off the SATA NCQ (native
59 command queueing) priority support. By default this feature is
60 turned off. If the device does not support the SATA NCQ
61 priority feature, writing "1" to this file results in an error
62 (see ncq_prio_supported).
63
64
65What: /sys/block/*/device/sas_ncq_prio_enable
66Date: Oct, 2016
67KernelVersion: v4.10
68Contact: linux-ide@vger.kernel.org
69Description:
70 (RW) This is the equivalent of the ncq_prio_enable attribute
71 file for SATA devices connected to a SAS host-bus-adapter
72 (HBA) implementing support for the SATA NCQ priority feature.
73 This file does not exist if the HBA driver does not implement
74 support for the SATA NCQ priority feature, regardless of the
75 device support for this feature (see sas_ncq_prio_supported).
76
77
78What: /sys/block/*/device/ncq_prio_supported
79Date: Aug, 2021
80KernelVersion: v5.15
81Contact: linux-ide@vger.kernel.org
82Description:
83 (RO) Indicates if the device supports the SATA NCQ (native
84 command queueing) priority feature.
85
86
87What: /sys/block/*/device/sas_ncq_prio_supported
88Date: Aug, 2021
89KernelVersion: v5.15
90Contact: linux-ide@vger.kernel.org
91Description:
92 (RO) This is the equivalent of the ncq_prio_supported attribute
93 file for SATA devices connected to a SAS host-bus-adapter
94 (HBA) implementing support for the SATA NCQ priority feature.
95 This file does not exist if the HBA driver does not implement
96 support for the SATA NCQ priority feature, regardless of the
97 device support for this feature.
1What: /sys/block/*/device/sw_activity
2Date: Jun, 2008
3KernelVersion: v2.6.27
4Contact: linux-ide@vger.kernel.org
5Description:
6 (RW) Used by drivers which support software controlled activity
7 LEDs.
8
9 It has the following valid values:
10
11 == ========================================================
12 0 OFF - the LED is not activated on activity
13 1 BLINK_ON - the LED blinks on every 10ms when activity is
14 detected.
15 2 BLINK_OFF - the LED is on when idle, and blinks off
16 every 10ms when activity is detected.
17 == ========================================================
18
19 Note that the user must turn sw_activity OFF it they wish to
20 control the activity LED via the em_message file.
21
22
23What: /sys/block/*/device/unload_heads
24Date: Sep, 2008
25KernelVersion: v2.6.28
26Contact: linux-ide@vger.kernel.org
27Description:
28 (RW) Hard disk shock protection
29
30 Writing an integer value to this file will take the heads of the
31 respective drive off the platter and block all I/O operations
32 for the specified number of milliseconds.
33
34 - If the device does not support the unload heads feature,
35 access is denied with -EOPNOTSUPP.
36 - The maximal value accepted for a timeout is 30000
37 milliseconds.
38 - A previously set timeout can be cancelled and disk can resume
39 normal operation immediately by specifying a timeout of 0.
40 - Some hard drives only comply with an earlier version of the
41 ATA standard, but support the unload feature nonetheless.
42 There is no safe way Linux can detect these devices, so this
43 is not enabled by default. If it is known that your device
44 does support the unload feature, then you can tell the kernel
45 to enable it by writing -1. It can be disabled again by
46 writing -2.
47 - Values below -2 are rejected with -EINVAL
48
49 For more information, see
50 Documentation/admin-guide/laptops/disk-shock-protection.rst
51
52
53What: /sys/block/*/device/ncq_prio_enable
54Date: Oct, 2016
55KernelVersion: v4.10
56Contact: linux-ide@vger.kernel.org
57Description:
58 (RW) Write to the file to turn on or off the SATA NCQ (native
59 command queueing) priority support. By default this feature is
60 turned off. If the device does not support the SATA NCQ
61 priority feature, writing "1" to this file results in an error
62 (see ncq_prio_supported).
63
64
65What: /sys/block/*/device/sas_ncq_prio_enable
66Date: Oct, 2016
67KernelVersion: v4.10
68Contact: linux-ide@vger.kernel.org
69Description:
70 (RW) This is the equivalent of the ncq_prio_enable attribute
71 file for SATA devices connected to a SAS host-bus-adapter
72 (HBA) implementing support for the SATA NCQ priority feature.
73 This file does not exist if the HBA driver does not implement
74 support for the SATA NCQ priority feature, regardless of the
75 device support for this feature (see sas_ncq_prio_supported).
76
77
78What: /sys/block/*/device/ncq_prio_supported
79Date: Aug, 2021
80KernelVersion: v5.15
81Contact: linux-ide@vger.kernel.org
82Description:
83 (RO) Indicates if the device supports the SATA NCQ (native
84 command queueing) priority feature.
85
86
87What: /sys/block/*/device/sas_ncq_prio_supported
88Date: Aug, 2021
89KernelVersion: v5.15
90Contact: linux-ide@vger.kernel.org
91Description:
92 (RO) This is the equivalent of the ncq_prio_supported attribute
93 file for SATA devices connected to a SAS host-bus-adapter
94 (HBA) implementing support for the SATA NCQ priority feature.
95 This file does not exist if the HBA driver does not implement
96 support for the SATA NCQ priority feature, regardless of the
97 device support for this feature.
98
99
100What: /sys/block/*/device/cdl_supported
101Date: May, 2023
102KernelVersion: v6.5
103Contact: linux-scsi@vger.kernel.org
104Description:
105 (RO) Indicates if the device supports the command duration
106 limits feature found in some ATA and SCSI devices.
107
108
109What: /sys/block/*/device/cdl_enable
110Date: May, 2023
111KernelVersion: v6.5
112Contact: linux-scsi@vger.kernel.org
113Description:
114 (RW) For a device supporting the command duration limits
115 feature, write to the file to turn on or off the feature.
116 By default this feature is turned off.
117 Writing "1" to this file enables the use of command duration
118 limits for read and write commands in the kernel and turns on
119 the feature on the device. Writing "0" disables the feature.