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author | Mauro Carvalho Chehab <mchehab@s-opensource.com> | 2016-07-08 17:40:06 +0300 |
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committer | Mauro Carvalho Chehab <mchehab@s-opensource.com> | 2016-07-08 17:59:40 +0300 |
commit | 60c2820d0f6d3497975b6488e2599f8f611d8b95 (patch) | |
tree | b3b03707c6438ea9b99cc57e847ebf517f968ab1 /Documentation/media/uapi/dvb/fe-read-status.rst | |
parent | a97369b5e21ea9b8b5fef7c0f4f48bbe60c07ca3 (diff) | |
download | linux-60c2820d0f6d3497975b6488e2599f8f611d8b95.tar.xz |
doc_rst: rename the media Sphinx suff to Documentation/media
The name of the subsystem is "media", and not "linux_tv". Also,
as we plan to add other stuff there in the future, let's
rename also the media uAPI book to media_uapi, to make it
clearer.
No functional changes.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Diffstat (limited to 'Documentation/media/uapi/dvb/fe-read-status.rst')
-rw-r--r-- | Documentation/media/uapi/dvb/fe-read-status.rst | 135 |
1 files changed, 135 insertions, 0 deletions
diff --git a/Documentation/media/uapi/dvb/fe-read-status.rst b/Documentation/media/uapi/dvb/fe-read-status.rst new file mode 100644 index 000000000000..339955fbe133 --- /dev/null +++ b/Documentation/media/uapi/dvb/fe-read-status.rst @@ -0,0 +1,135 @@ +.. -*- coding: utf-8; mode: rst -*- + +.. _FE_READ_STATUS: + +******************** +ioctl FE_READ_STATUS +******************** + +Name +==== + +FE_READ_STATUS - Returns status information about the front-end. This call only requires - read-only access to the device + + +Synopsis +======== + +.. cpp:function:: int ioctl( int fd, int request, unsigned int *status ) + + +Arguments +========= + +``fd`` + File descriptor returned by :ref:`open() <frontend_f_open>`. + +``request`` + FE_READ_STATUS + +``status`` + pointer to a bitmask integer filled with the values defined by enum + :ref:`fe_status <fe-status>`. + + +Description +=========== + +All DVB frontend devices support the ``FE_READ_STATUS`` ioctl. It is +used to check about the locking status of the frontend after being +tuned. The ioctl takes a pointer to an integer where the status will be +written. + +NOTE: the size of status is actually sizeof(enum fe_status), with +varies according with the architecture. This needs to be fixed in the +future. + + +.. _fe-status-t: + +int fe_status +============= + +The fe_status parameter is used to indicate the current state and/or +state changes of the frontend hardware. It is produced using the enum +:ref:`fe_status <fe-status>` values on a bitmask + + +.. _fe-status: + +.. flat-table:: enum fe_status + :header-rows: 1 + :stub-columns: 0 + + + - .. row 1 + + - ID + + - Description + + - .. row 2 + + - .. _FE-HAS-SIGNAL: + + ``FE_HAS_SIGNAL`` + + - The frontend has found something above the noise level + + - .. row 3 + + - .. _FE-HAS-CARRIER: + + ``FE_HAS_CARRIER`` + + - The frontend has found a DVB signal + + - .. row 4 + + - .. _FE-HAS-VITERBI: + + ``FE_HAS_VITERBI`` + + - The frontend FEC inner coding (Viterbi, LDPC or other inner code) + is stable + + - .. row 5 + + - .. _FE-HAS-SYNC: + + ``FE_HAS_SYNC`` + + - Synchronization bytes was found + + - .. row 6 + + - .. _FE-HAS-LOCK: + + ``FE_HAS_LOCK`` + + - The DVB were locked and everything is working + + - .. row 7 + + - .. _FE-TIMEDOUT: + + ``FE_TIMEDOUT`` + + - no lock within the last about 2 seconds + + - .. row 8 + + - .. _FE-REINIT: + + ``FE_REINIT`` + + - The frontend was reinitialized, application is recommended to + reset DiSEqC, tone and parameters + + +Return Value +============ + +On success 0 is returned, on error -1 and the ``errno`` variable is set +appropriately. The generic error codes are described at the +:ref:`Generic Error Codes <gen-errors>` chapter. |