| Rafael J. Wysocki | 95c513e | 2018-03-16 13:51:01 +0100 | [diff] [blame^] | 1 | ACPI Time and Alarm (TAD) device attributes. |
| 2 | |
| 3 | What: /sys/bus/platform/devices/ACPI000E:00/caps |
| 4 | Date: March 2018 |
| 5 | Contact: Rafael J. Wysocki <rafael.j.wysocki@intel.com> |
| 6 | Description: |
| 7 | (RO) Hexadecimal bitmask of the TAD attributes are reported by |
| 8 | the platform firmware (see ACPI 6.2, section 9.18.2): |
| 9 | |
| 10 | BIT(0): AC wakeup implemented if set |
| 11 | BIT(1): DC wakeup implemented if set |
| 12 | BIT(2): Get/set real time features implemented if set |
| 13 | BIT(3): Real time accuracy in milliseconds if set |
| 14 | BIT(4): Correct status reported for wakeups from S4/S5 if set |
| 15 | BIT(5): The AC timer wakes up from S4 if set |
| 16 | BIT(6): The AC timer wakes up from S5 if set |
| 17 | BIT(7): The DC timer wakes up from S4 if set |
| 18 | BIT(8): The DC timer wakes up from S5 if set |
| 19 | |
| 20 | The other bits are reserved. |
| 21 | |
| 22 | What: /sys/bus/platform/devices/ACPI000E:00/ac_alarm |
| 23 | Date: March 2018 |
| 24 | Contact: Rafael J. Wysocki <rafael.j.wysocki@intel.com> |
| 25 | Description: |
| 26 | (RW) The AC alarm timer value. |
| 27 | |
| 28 | Reads return the current AC alarm timer value in seconds or |
| 29 | "disabled", if the AC alarm is not set to wake up the system. |
| 30 | |
| 31 | Write a new AC alarm timer value in seconds or "disabled" to it |
| 32 | to set the AC alarm timer or to disable it, respectively. |
| 33 | |
| 34 | If the AC alarm timer is set through this attribute and it |
| 35 | expires, it will immediately wake up the system from the S3 |
| 36 | sleep state (and from S4/S5 too if supported) until its status |
| 37 | is explicitly cleared via the ac_status attribute. |
| 38 | |
| 39 | What: /sys/bus/platform/devices/ACPI000E:00/ac_policy |
| 40 | Date: March 2018 |
| 41 | Contact: Rafael J. Wysocki <rafael.j.wysocki@intel.com> |
| 42 | Description: |
| 43 | (RW) The AC alarm expired timer wake policy (see ACPI 6.2, |
| 44 | Section 9.18 for details). |
| 45 | |
| 46 | Reads return the current expired timer wake delay for the AC |
| 47 | alarm timer or "never", if the policy is to discard AC timer |
| 48 | wakeups if the system is on DC power. |
| 49 | |
| 50 | Write a new expired timer wake delay for the AC alarm timer in |
| 51 | seconds or "never" to it to set the expired timer wake delay for |
| 52 | the AC alarm timer or to set its expired wake policy to discard |
| 53 | wakeups if the system is on DC power, respectively. |
| 54 | |
| 55 | What: /sys/bus/platform/devices/ACPI000E:00/ac_status |
| 56 | Date: March 2018 |
| 57 | Contact: Rafael J. Wysocki <rafael.j.wysocki@intel.com> |
| 58 | Description: |
| 59 | (RW) The AC alarm status. |
| 60 | |
| 61 | Reads return a hexadecimal bitmask representing the AC alarm |
| 62 | timer status with the following meaning of bits (see ACPI 6.2, |
| 63 | Section 9.18.5): |
| 64 | |
| 65 | Bit(0): The timer has expired if set. |
| 66 | Bit(1): The timer has woken up the system from a sleep state |
| 67 | (S3 or S4/S5 if supported) if set. |
| 68 | |
| 69 | The other bits are reserved. |
| 70 | |
| 71 | Reads also cause the AC alarm timer status to be reset. |
| 72 | |
| 73 | Another way to reset the the status of the AC alarm timer is to |
| 74 | write (the number) 0 to this file. |
| 75 | |
| 76 | If the status return value indicates that the timer has expired, |
| 77 | it will immediately wake up the system from the S3 sleep state |
| 78 | (and from S4/S5 too if supported) until its status is explicitly |
| 79 | cleared through this attribute. |
| 80 | |
| 81 | What: /sys/bus/platform/devices/ACPI000E:00/dc_alarm |
| 82 | Date: March 2018 |
| 83 | Contact: Rafael J. Wysocki <rafael.j.wysocki@intel.com> |
| 84 | Description: |
| 85 | (RW,optional) The DC alarm timer value. |
| 86 | |
| 87 | This attribute is only present if the TAD supports a separate |
| 88 | DC timer. |
| 89 | |
| 90 | It is analogous to the ac_alarm attribute. |
| 91 | |
| 92 | What: /sys/bus/platform/devices/ACPI000E:00/dc_policy |
| 93 | Date: March 2018 |
| 94 | Contact: Rafael J. Wysocki <rafael.j.wysocki@intel.com> |
| 95 | Description: |
| 96 | (RW,optional) The DC alarm expired timer wake policy. |
| 97 | |
| 98 | This attribute is only present if the TAD supports a separate |
| 99 | DC timer. |
| 100 | |
| 101 | It is analogous to the ac_policy attribute. |
| 102 | |
| 103 | What: /sys/bus/platform/devices/ACPI000E:00/dc_status |
| 104 | Date: March 2018 |
| 105 | Contact: Rafael J. Wysocki <rafael.j.wysocki@intel.com> |
| 106 | |
| 107 | Description: |
| 108 | (RW,optional) The DC alarm status. |
| 109 | |
| 110 | This attribute is only present if the TAD supports a separate |
| 111 | DC timer. |
| 112 | |
| 113 | It is analogous to the ac_status attribute. |