Documentation/media/uapi/dvb/fe-read-status.rst

   1 .. -*- coding: utf-8; mode: rst -*-
   2
   3 .. _FE_READ_STATUS:
   4
   5 ********************
   6 ioctl FE_READ_STATUS
   7 ********************
   8
   9 Name
  10 ====
  11
  12 FE_READ_STATUS - Returns status information about the front-end. This call only requires - read-only access to the device
  13
  14
  15 Synopsis
  16 ========
  17
  18 .. cpp:function:: int ioctl( int fd, int request, unsigned int *status )
  19
  20
  21 Arguments
  22 =========
  23
  24 ``fd``
  25     File descriptor returned by :ref:`open() <frontend_f_open>`.
  26
  27 ``request``
  28     FE_READ_STATUS
  29
  30 ``status``
  31     pointer to a bitmask integer filled with the values defined by enum
  32     :ref:`fe_status <fe-status>`.
  33
  34
  35 Description
  36 ===========
  37
  38 All DVB frontend devices support the ``FE_READ_STATUS`` ioctl. It is
  39 used to check about the locking status of the frontend after being
  40 tuned. The ioctl takes a pointer to an integer where the status will be
  41 written.
  42
  43 .. note:: The size of status is actually sizeof(enum fe_status), with
  44    varies according with the architecture. This needs to be fixed in the
  45    future.
  46
  47
  48 .. _fe-status-t:
  49
  50 int fe_status
  51 =============
  52
  53 The fe_status parameter is used to indicate the current state and/or
  54 state changes of the frontend hardware. It is produced using the enum
  55 :ref:`fe_status <fe-status>` values on a bitmask
  56
  57
  58 .. _fe-status:
  59
  60 .. flat-table:: enum fe_status
  61     :header-rows:  1
  62     :stub-columns: 0
  63
  64
  65     -  .. row 1
  66
  67        -  ID
  68
  69        -  Description
  70
  71     -  .. row 2
  72
  73        -  .. _FE-HAS-SIGNAL:
  74
  75           ``FE_HAS_SIGNAL``
  76
  77        -  The frontend has found something above the noise level
  78
  79     -  .. row 3
  80
  81        -  .. _FE-HAS-CARRIER:
  82
  83           ``FE_HAS_CARRIER``
  84
  85        -  The frontend has found a DVB signal
  86
  87     -  .. row 4
  88
  89        -  .. _FE-HAS-VITERBI:
  90
  91           ``FE_HAS_VITERBI``
  92
  93        -  The frontend FEC inner coding (Viterbi, LDPC or other inner code)
  94           is stable
  95
  96     -  .. row 5
  97
  98        -  .. _FE-HAS-SYNC:
  99
 100           ``FE_HAS_SYNC``
 101
 102        -  Synchronization bytes was found
 103
 104     -  .. row 6
 105
 106        -  .. _FE-HAS-LOCK:
 107
 108           ``FE_HAS_LOCK``
 109
 110        -  The DVB were locked and everything is working
 111
 112     -  .. row 7
 113
 114        -  .. _FE-TIMEDOUT:
 115
 116           ``FE_TIMEDOUT``
 117
 118        -  no lock within the last about 2 seconds
 119
 120     -  .. row 8
 121
 122        -  .. _FE-REINIT:
 123
 124           ``FE_REINIT``
 125
 126        -  The frontend was reinitialized, application is recommended to
 127           reset DiSEqC, tone and parameters
 128
 129
 130 Return Value
 131 ============
 132
 133 On success 0 is returned, on error -1 and the ``errno`` variable is set
 134 appropriately. The generic error codes are described at the
 135 :ref:`Generic Error Codes <gen-errors>` chapter.