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authorLinus Torvalds <torvalds@linux-foundation.org>2016-07-27 23:58:31 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2016-07-27 23:58:31 +0200
commitff9a082fda424257976f08fce942609f358015e0 (patch)
tree478e6b449b19baaf842369a13923499ce83ef895 /Documentation/media/uapi/dvb/fe-read-status.rst
parentMerge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi (diff)
parentMerge branch 'topic/docs-next' into v4l_for_linus (diff)
downloadlinux-ff9a082fda424257976f08fce942609f358015e0.tar.xz
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Merge tag 'media/v4.8-4' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media
Pull media documentation updates from Mauro Carvalho Chehab: "This patch series does the conversion of all media documentation stuff to Restrutured Text markup format and add them to the Documentation/index.rst file. The media documentation was grouped into 4 books: - media uAPI - media kAPI - V4L driver-specific documentation - DVB driver-specific documentation It also contains several documentation improvements and one fixup patch for a core issue with cropcap. PS. After this patch series, the media DocBook is deprecated and should be removed. I'll add such patch on a future pull request" * tag 'media/v4.8-4' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (322 commits) [media] cx23885-cardlist.rst: add a new card [media] doc-rst: add some needed escape codes [media] doc-rst: kapi: use :c:func: instead of :cpp:func doc-rst: kernel-doc: fix a change introduced by mistake [media] v4l2-ioctl.h add debug info for struct v4l2_ioctl_ops [media] dvb_ringbuffer.h: some documentation improvements [media] v4l2-ctrls.h: fully document the header file [media] doc-rst: Fix some typedef ugly warnings [media] doc-rst: reorganize the kAPI v4l2 chapters [media] rename v4l2-framework.rst to v4l2-intro.rst [media] move V4L2 clocks to a separate .rst file [media] v4l2-fh.rst: add cross references and markups [media] v4l2-fh.rst: add fh contents from v4l2-framework.rst [media] v4l2-fh.h: add documentation for it [media] v4l2-event.rst: add cross-references and markups [media] v4l2-event.h: document all functions [media] v4l2-event.rst: add text from v4l2-framework.rst [media] v4l2-framework.rst: remove videobuf quick chapter [media] v4l2-dev: add cross-references and improve markup [media] doc-rst: move v4l2-dev doc to a separate file ...
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+.. -*- 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.