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 .. c:function:: int ioctl( int fd, FE_READ_STATUS, unsigned int *status )
  19     :name: FE_READ_STATUS
  20
  21
  22 Arguments
  23 =========
  24
  25 ``fd``
  26     File descriptor returned by :ref:`open() <frontend_f_open>`.
  27
  28 ``status``
  29     pointer to a bitmask integer filled with the values defined by enum
  30     :c:type:`fe_status`.
  31
  32
  33 Description
  34 ===========
  35
  36 All DVB frontend devices support the ``FE_READ_STATUS`` ioctl. It is
  37 used to check about the locking status of the frontend after being
  38 tuned. The ioctl takes a pointer to an integer where the status will be
  39 written.
  40
  41 .. note::
  42
  43    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 int fe_status
  49 =============
  50
  51 The fe_status parameter is used to indicate the current state and/or
  52 state changes of the frontend hardware. It is produced using the enum
  53 :c:type:`fe_status` values on a bitmask
  54
  55 .. c:type:: fe_status
  56
  57 .. tabularcolumns:: |p{3.5cm}|p{14.0cm}|
  58
  59 .. _fe-status:
  60
  61 .. flat-table:: enum fe_status
  62     :header-rows:  1
  63     :stub-columns: 0
  64
  65
  66     -  .. row 1
  67
  68        -  ID
  69
  70        -  Description
  71
  72     -  .. row 2
  73
  74        -  .. _FE-HAS-SIGNAL:
  75
  76           ``FE_HAS_SIGNAL``
  77
  78        -  The frontend has found something above the noise level
  79
  80     -  .. row 3
  81
  82        -  .. _FE-HAS-CARRIER:
  83
  84           ``FE_HAS_CARRIER``
  85
  86        -  The frontend has found a DVB signal
  87
  88     -  .. row 4
  89
  90        -  .. _FE-HAS-VITERBI:
  91
  92           ``FE_HAS_VITERBI``
  93
  94        -  The frontend FEC inner coding (Viterbi, LDPC or other inner code)
  95           is stable
  96
  97     -  .. row 5
  98
  99        -  .. _FE-HAS-SYNC:
 100
 101           ``FE_HAS_SYNC``
 102
 103        -  Synchronization bytes was found
 104
 105     -  .. row 6
 106
 107        -  .. _FE-HAS-LOCK:
 108
 109           ``FE_HAS_LOCK``
 110
 111        -  The DVB were locked and everything is working
 112
 113     -  .. row 7
 114
 115        -  .. _FE-TIMEDOUT:
 116
 117           ``FE_TIMEDOUT``
 118
 119        -  no lock within the last about 2 seconds
 120
 121     -  .. row 8
 122
 123        -  .. _FE-REINIT:
 124
 125           ``FE_REINIT``
 126
 127        -  The frontend was reinitialized, application is recommended to
 128           reset DiSEqC, tone and parameters
 129
 130
 131 Return Value
 132 ============
 133
 134 On success 0 is returned, on error -1 and the ``errno`` variable is set
 135 appropriately. The generic error codes are described at the
 136 :ref:`Generic Error Codes <gen-errors>` chapter.