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Rafael J. Wysocki95c513e2018-03-16 13:51:01 +01001 ACPI Time and Alarm (TAD) device attributes.
2
3What: /sys/bus/platform/devices/ACPI000E:00/caps
4Date: March 2018
5Contact: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
6Description:
7 (RO) Hexadecimal bitmask of the TAD attributes are reported by
8 the platform firmware (see ACPI 6.2, section 9.18.2):
9
Mauro Carvalho Chehab34433332020-10-30 08:40:39 +010010 ======= ======================================================
Rafael J. Wysocki95c513e2018-03-16 13:51:01 +010011 BIT(0): AC wakeup implemented if set
12 BIT(1): DC wakeup implemented if set
13 BIT(2): Get/set real time features implemented if set
14 BIT(3): Real time accuracy in milliseconds if set
15 BIT(4): Correct status reported for wakeups from S4/S5 if set
16 BIT(5): The AC timer wakes up from S4 if set
17 BIT(6): The AC timer wakes up from S5 if set
18 BIT(7): The DC timer wakes up from S4 if set
19 BIT(8): The DC timer wakes up from S5 if set
Mauro Carvalho Chehab34433332020-10-30 08:40:39 +010020 ======= ======================================================
Rafael J. Wysocki95c513e2018-03-16 13:51:01 +010021
22 The other bits are reserved.
23
24What: /sys/bus/platform/devices/ACPI000E:00/ac_alarm
25Date: March 2018
26Contact: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
27Description:
28 (RW) The AC alarm timer value.
29
30 Reads return the current AC alarm timer value in seconds or
31 "disabled", if the AC alarm is not set to wake up the system.
32
33 Write a new AC alarm timer value in seconds or "disabled" to it
34 to set the AC alarm timer or to disable it, respectively.
35
36 If the AC alarm timer is set through this attribute and it
37 expires, it will immediately wake up the system from the S3
38 sleep state (and from S4/S5 too if supported) until its status
39 is explicitly cleared via the ac_status attribute.
40
41What: /sys/bus/platform/devices/ACPI000E:00/ac_policy
42Date: March 2018
43Contact: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
44Description:
45 (RW) The AC alarm expired timer wake policy (see ACPI 6.2,
46 Section 9.18 for details).
47
48 Reads return the current expired timer wake delay for the AC
49 alarm timer or "never", if the policy is to discard AC timer
50 wakeups if the system is on DC power.
51
52 Write a new expired timer wake delay for the AC alarm timer in
53 seconds or "never" to it to set the expired timer wake delay for
54 the AC alarm timer or to set its expired wake policy to discard
55 wakeups if the system is on DC power, respectively.
56
57What: /sys/bus/platform/devices/ACPI000E:00/ac_status
58Date: March 2018
59Contact: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
60Description:
61 (RW) The AC alarm status.
62
63 Reads return a hexadecimal bitmask representing the AC alarm
64 timer status with the following meaning of bits (see ACPI 6.2,
65 Section 9.18.5):
66
Mauro Carvalho Chehab34433332020-10-30 08:40:39 +010067 ======= ======================================================
Rafael J. Wysocki95c513e2018-03-16 13:51:01 +010068 Bit(0): The timer has expired if set.
69 Bit(1): The timer has woken up the system from a sleep state
70 (S3 or S4/S5 if supported) if set.
Mauro Carvalho Chehab34433332020-10-30 08:40:39 +010071 ======= ======================================================
Rafael J. Wysocki95c513e2018-03-16 13:51:01 +010072
73 The other bits are reserved.
74
75 Reads also cause the AC alarm timer status to be reset.
76
77 Another way to reset the the status of the AC alarm timer is to
78 write (the number) 0 to this file.
79
80 If the status return value indicates that the timer has expired,
81 it will immediately wake up the system from the S3 sleep state
82 (and from S4/S5 too if supported) until its status is explicitly
83 cleared through this attribute.
84
85What: /sys/bus/platform/devices/ACPI000E:00/dc_alarm
86Date: March 2018
87Contact: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
88Description:
89 (RW,optional) The DC alarm timer value.
90
91 This attribute is only present if the TAD supports a separate
92 DC timer.
93
94 It is analogous to the ac_alarm attribute.
95
96What: /sys/bus/platform/devices/ACPI000E:00/dc_policy
97Date: March 2018
98Contact: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
99Description:
100 (RW,optional) The DC alarm expired timer wake policy.
101
102 This attribute is only present if the TAD supports a separate
103 DC timer.
104
105 It is analogous to the ac_policy attribute.
106
107What: /sys/bus/platform/devices/ACPI000E:00/dc_status
108Date: March 2018
109Contact: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
110
111Description:
112 (RW,optional) The DC alarm status.
113
114 This attribute is only present if the TAD supports a separate
115 DC timer.
116
117 It is analogous to the ac_status attribute.