Markus Heiser | e2460b1 | 2016-07-08 20:55:42 +0200 | [diff] [blame] | 1 | .. -*- coding: utf-8; mode: rst -*- |
| 2 | |
Markus Heiser | 21c6269 | 2016-07-08 20:55:43 +0200 | [diff] [blame] | 3 | .. _CEC_DQEVENT: |
Markus Heiser | e2460b1 | 2016-07-08 20:55:42 +0200 | [diff] [blame] | 4 | |
| 5 | ***************** |
| 6 | ioctl CEC_DQEVENT |
| 7 | ***************** |
| 8 | |
Markus Heiser | 21c6269 | 2016-07-08 20:55:43 +0200 | [diff] [blame] | 9 | Name |
| 10 | ==== |
Markus Heiser | e2460b1 | 2016-07-08 20:55:42 +0200 | [diff] [blame] | 11 | |
Markus Heiser | 21c6269 | 2016-07-08 20:55:43 +0200 | [diff] [blame] | 12 | CEC_DQEVENT - Dequeue a CEC event |
Markus Heiser | e2460b1 | 2016-07-08 20:55:42 +0200 | [diff] [blame] | 13 | |
| 14 | |
| 15 | Synopsis |
| 16 | ======== |
| 17 | |
Markus Heiser | 21c6269 | 2016-07-08 20:55:43 +0200 | [diff] [blame] | 18 | .. cpp:function:: int ioctl( int fd, int request, struct cec_event *argp ) |
Markus Heiser | e2460b1 | 2016-07-08 20:55:42 +0200 | [diff] [blame] | 19 | |
| 20 | Arguments |
| 21 | ========= |
| 22 | |
| 23 | ``fd`` |
| 24 | File descriptor returned by :ref:`open() <cec-func-open>`. |
| 25 | |
| 26 | ``request`` |
| 27 | CEC_DQEVENT |
| 28 | |
| 29 | ``argp`` |
| 30 | |
| 31 | |
| 32 | Description |
| 33 | =========== |
| 34 | |
Mauro Carvalho Chehab | 706f8a9 | 2016-07-10 11:57:43 -0300 | [diff] [blame] | 35 | .. note:: This documents the proposed CEC API. This API is not yet finalized |
| 36 | and is currently only available as a staging kernel module. |
Markus Heiser | e2460b1 | 2016-07-08 20:55:42 +0200 | [diff] [blame] | 37 | |
| 38 | CEC devices can send asynchronous events. These can be retrieved by |
Hans Verkuil | 1267c60 | 2016-07-13 08:48:54 -0300 | [diff] [blame] | 39 | calling :ref:`ioctl CEC_DQEVENT <CEC_DQEVENT>`. If the file descriptor is in |
Markus Heiser | e2460b1 | 2016-07-08 20:55:42 +0200 | [diff] [blame] | 40 | non-blocking mode and no event is pending, then it will return -1 and |
Hans Verkuil | e5208ed | 2016-07-19 06:26:13 -0300 | [diff] [blame^] | 41 | set errno to the ``EAGAIN`` error code. |
Markus Heiser | e2460b1 | 2016-07-08 20:55:42 +0200 | [diff] [blame] | 42 | |
| 43 | The internal event queues are per-filehandle and per-event type. If |
| 44 | there is no more room in a queue then the last event is overwritten with |
| 45 | the new one. This means that intermediate results can be thrown away but |
| 46 | that the latest event is always available. This also means that is it |
| 47 | possible to read two successive events that have the same value (e.g. |
Mauro Carvalho Chehab | cc0fe5c | 2016-07-13 10:22:38 -0300 | [diff] [blame] | 48 | two :ref:`CEC_EVENT_STATE_CHANGE <CEC-EVENT-STATE-CHANGE>` events with |
| 49 | the same state). In that case the intermediate state changes were lost but |
| 50 | it is guaranteed that the state did change in between the two events. |
Markus Heiser | e2460b1 | 2016-07-08 20:55:42 +0200 | [diff] [blame] | 51 | |
| 52 | |
Mauro Carvalho Chehab | 96f69e0 | 2016-07-09 10:25:05 -0300 | [diff] [blame] | 53 | .. _cec-event-state-change_s: |
Markus Heiser | e2460b1 | 2016-07-08 20:55:42 +0200 | [diff] [blame] | 54 | |
| 55 | .. flat-table:: struct cec_event_state_change |
| 56 | :header-rows: 0 |
| 57 | :stub-columns: 0 |
Mauro Carvalho Chehab | b2a5843 | 2016-07-08 17:59:27 -0300 | [diff] [blame] | 58 | :widths: 1 1 8 |
Markus Heiser | e2460b1 | 2016-07-08 20:55:42 +0200 | [diff] [blame] | 59 | |
| 60 | |
| 61 | - .. row 1 |
| 62 | |
| 63 | - __u16 |
| 64 | |
| 65 | - ``phys_addr`` |
| 66 | |
| 67 | - The current physical address. |
| 68 | |
| 69 | - .. row 2 |
| 70 | |
| 71 | - __u16 |
| 72 | |
| 73 | - ``log_addr_mask`` |
| 74 | |
| 75 | - The current set of claimed logical addresses. |
| 76 | |
| 77 | |
| 78 | |
Mauro Carvalho Chehab | 96f69e0 | 2016-07-09 10:25:05 -0300 | [diff] [blame] | 79 | .. _cec-event-lost-msgs_s: |
Markus Heiser | e2460b1 | 2016-07-08 20:55:42 +0200 | [diff] [blame] | 80 | |
| 81 | .. flat-table:: struct cec_event_lost_msgs |
| 82 | :header-rows: 0 |
| 83 | :stub-columns: 0 |
Mauro Carvalho Chehab | b2a5843 | 2016-07-08 17:59:27 -0300 | [diff] [blame] | 84 | :widths: 1 1 16 |
Markus Heiser | e2460b1 | 2016-07-08 20:55:42 +0200 | [diff] [blame] | 85 | |
| 86 | |
| 87 | - .. row 1 |
| 88 | |
| 89 | - __u32 |
| 90 | |
| 91 | - ``lost_msgs`` |
| 92 | |
| 93 | - Set to the number of lost messages since the filehandle was opened |
Mauro Carvalho Chehab | 706f8a9 | 2016-07-10 11:57:43 -0300 | [diff] [blame] | 94 | or since the last time this event was dequeued for this |
| 95 | filehandle. The messages lost are the oldest messages. So when a |
| 96 | new message arrives and there is no more room, then the oldest |
| 97 | message is discarded to make room for the new one. The internal |
| 98 | size of the message queue guarantees that all messages received in |
| 99 | the last two seconds will be stored. Since messages should be |
| 100 | replied to within a second according to the CEC specification, |
| 101 | this is more than enough. |
Markus Heiser | e2460b1 | 2016-07-08 20:55:42 +0200 | [diff] [blame] | 102 | |
| 103 | |
| 104 | |
| 105 | .. _cec-event: |
| 106 | |
| 107 | .. flat-table:: struct cec_event |
| 108 | :header-rows: 0 |
| 109 | :stub-columns: 0 |
Mauro Carvalho Chehab | b2a5843 | 2016-07-08 17:59:27 -0300 | [diff] [blame] | 110 | :widths: 1 1 1 8 |
Markus Heiser | e2460b1 | 2016-07-08 20:55:42 +0200 | [diff] [blame] | 111 | |
| 112 | |
| 113 | - .. row 1 |
| 114 | |
| 115 | - __u64 |
| 116 | |
| 117 | - ``ts`` |
| 118 | |
| 119 | - Timestamp of the event in ns. |
Hans Verkuil | e5208ed | 2016-07-19 06:26:13 -0300 | [diff] [blame^] | 120 | The timestamp has been taken from the ``CLOCK_MONOTONIC`` clock. To access |
| 121 | the same clock from userspace use :c:func:`clock_gettime(2)`. |
Markus Heiser | e2460b1 | 2016-07-08 20:55:42 +0200 | [diff] [blame] | 122 | |
| 123 | - |
| 124 | |
| 125 | - .. row 2 |
| 126 | |
| 127 | - __u32 |
| 128 | |
| 129 | - ``event`` |
| 130 | |
| 131 | - The CEC event type, see :ref:`cec-events`. |
| 132 | |
| 133 | - |
| 134 | |
| 135 | - .. row 3 |
| 136 | |
| 137 | - __u32 |
| 138 | |
| 139 | - ``flags`` |
| 140 | |
| 141 | - Event flags, see :ref:`cec-event-flags`. |
| 142 | |
| 143 | - |
| 144 | |
| 145 | - .. row 4 |
| 146 | |
| 147 | - union |
| 148 | |
| 149 | - (anonymous) |
| 150 | |
| 151 | - |
| 152 | - |
| 153 | |
| 154 | - .. row 5 |
| 155 | |
| 156 | - |
| 157 | - struct cec_event_state_change |
| 158 | |
| 159 | - ``state_change`` |
| 160 | |
Mauro Carvalho Chehab | 96f69e0 | 2016-07-09 10:25:05 -0300 | [diff] [blame] | 161 | - The new adapter state as sent by the :ref:`CEC_EVENT_STATE_CHANGE <CEC-EVENT-STATE-CHANGE>` |
Mauro Carvalho Chehab | 706f8a9 | 2016-07-10 11:57:43 -0300 | [diff] [blame] | 162 | event. |
Markus Heiser | e2460b1 | 2016-07-08 20:55:42 +0200 | [diff] [blame] | 163 | |
| 164 | - .. row 6 |
| 165 | |
| 166 | - |
| 167 | - struct cec_event_lost_msgs |
| 168 | |
| 169 | - ``lost_msgs`` |
| 170 | |
Mauro Carvalho Chehab | 96f69e0 | 2016-07-09 10:25:05 -0300 | [diff] [blame] | 171 | - The number of lost messages as sent by the :ref:`CEC_EVENT_LOST_MSGS <CEC-EVENT-LOST-MSGS>` |
Mauro Carvalho Chehab | 706f8a9 | 2016-07-10 11:57:43 -0300 | [diff] [blame] | 172 | event. |
Markus Heiser | e2460b1 | 2016-07-08 20:55:42 +0200 | [diff] [blame] | 173 | |
| 174 | |
| 175 | |
| 176 | .. _cec-events: |
| 177 | |
| 178 | .. flat-table:: CEC Events Types |
| 179 | :header-rows: 0 |
| 180 | :stub-columns: 0 |
Mauro Carvalho Chehab | b2a5843 | 2016-07-08 17:59:27 -0300 | [diff] [blame] | 181 | :widths: 3 1 16 |
Markus Heiser | e2460b1 | 2016-07-08 20:55:42 +0200 | [diff] [blame] | 182 | |
| 183 | |
Mauro Carvalho Chehab | 96f69e0 | 2016-07-09 10:25:05 -0300 | [diff] [blame] | 184 | - .. _`CEC-EVENT-STATE-CHANGE`: |
Markus Heiser | e2460b1 | 2016-07-08 20:55:42 +0200 | [diff] [blame] | 185 | |
| 186 | - ``CEC_EVENT_STATE_CHANGE`` |
| 187 | |
| 188 | - 1 |
| 189 | |
| 190 | - Generated when the CEC Adapter's state changes. When open() is |
Mauro Carvalho Chehab | 706f8a9 | 2016-07-10 11:57:43 -0300 | [diff] [blame] | 191 | called an initial event will be generated for that filehandle with |
| 192 | the CEC Adapter's state at that time. |
Markus Heiser | e2460b1 | 2016-07-08 20:55:42 +0200 | [diff] [blame] | 193 | |
Mauro Carvalho Chehab | 96f69e0 | 2016-07-09 10:25:05 -0300 | [diff] [blame] | 194 | - .. _`CEC-EVENT-LOST-MSGS`: |
Markus Heiser | e2460b1 | 2016-07-08 20:55:42 +0200 | [diff] [blame] | 195 | |
| 196 | - ``CEC_EVENT_LOST_MSGS`` |
| 197 | |
| 198 | - 2 |
| 199 | |
| 200 | - Generated if one or more CEC messages were lost because the |
Mauro Carvalho Chehab | 706f8a9 | 2016-07-10 11:57:43 -0300 | [diff] [blame] | 201 | application didn't dequeue CEC messages fast enough. |
Markus Heiser | e2460b1 | 2016-07-08 20:55:42 +0200 | [diff] [blame] | 202 | |
| 203 | |
| 204 | |
| 205 | .. _cec-event-flags: |
| 206 | |
| 207 | .. flat-table:: CEC Event Flags |
| 208 | :header-rows: 0 |
| 209 | :stub-columns: 0 |
Mauro Carvalho Chehab | b2a5843 | 2016-07-08 17:59:27 -0300 | [diff] [blame] | 210 | :widths: 3 1 8 |
Markus Heiser | e2460b1 | 2016-07-08 20:55:42 +0200 | [diff] [blame] | 211 | |
| 212 | |
Mauro Carvalho Chehab | 96f69e0 | 2016-07-09 10:25:05 -0300 | [diff] [blame] | 213 | - .. _`CEC-EVENT-FL-INITIAL-VALUE`: |
Markus Heiser | e2460b1 | 2016-07-08 20:55:42 +0200 | [diff] [blame] | 214 | |
| 215 | - ``CEC_EVENT_FL_INITIAL_VALUE`` |
| 216 | |
| 217 | - 1 |
| 218 | |
| 219 | - Set for the initial events that are generated when the device is |
Mauro Carvalho Chehab | 706f8a9 | 2016-07-10 11:57:43 -0300 | [diff] [blame] | 220 | opened. See the table above for which events do this. This allows |
| 221 | applications to learn the initial state of the CEC adapter at |
| 222 | open() time. |
Markus Heiser | e2460b1 | 2016-07-08 20:55:42 +0200 | [diff] [blame] | 223 | |
| 224 | |
| 225 | |
| 226 | Return Value |
| 227 | ============ |
| 228 | |
| 229 | On success 0 is returned, on error -1 and the ``errno`` variable is set |
| 230 | appropriately. The generic error codes are described at the |
| 231 | :ref:`Generic Error Codes <gen-errors>` chapter. |