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diff --git a/Documentation/media/uapi/dvb/dvbproperty.rst b/Documentation/media/uapi/dvb/dvbproperty.rst deleted file mode 100644 index 0c4f5598f2be..000000000000 --- a/Documentation/media/uapi/dvb/dvbproperty.rst +++ /dev/null @@ -1,133 +0,0 @@ -.. Permission is granted to copy, distribute and/or modify this -.. document under the terms of the GNU Free Documentation License, -.. Version 1.1 or any later version published by the Free Software -.. Foundation, with no Invariant Sections, no Front-Cover Texts -.. and no Back-Cover Texts. A copy of the license is included at -.. Documentation/media/uapi/fdl-appendix.rst. -.. -.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections - -.. _frontend-properties: - -************** -Property types -************** - -Tuning into a Digital TV physical channel and starting decoding it -requires changing a set of parameters, in order to control the tuner, -the demodulator, the Linear Low-noise Amplifier (LNA) and to set the -antenna subsystem via Satellite Equipment Control - SEC (on satellite -systems). The actual parameters are specific to each particular digital -TV standards, and may change as the digital TV specs evolves. - -In the past (up to DVB API version 3 - DVBv3), the strategy used was to have a -union with the parameters needed to tune for DVB-S, DVB-C, DVB-T and -ATSC delivery systems grouped there. The problem is that, as the second -generation standards appeared, the size of such union was not big -enough to group the structs that would be required for those new -standards. Also, extending it would break userspace. - -So, the legacy union/struct based approach was deprecated, in favor -of a properties set approach. On such approach, -:ref:`FE_GET_PROPERTY and FE_SET_PROPERTY <FE_GET_PROPERTY>` are used -to setup the frontend and read its status. - -The actual action is determined by a set of dtv_property cmd/data pairs. -With one single ioctl, is possible to get/set up to 64 properties. - -This section describes the new and recommended way to set the frontend, -with supports all digital TV delivery systems. - -.. note:: - - 1. On Linux DVB API version 3, setting a frontend was done via - struct :c:type:`dvb_frontend_parameters`. - - 2. Don't use DVB API version 3 calls on hardware with supports - newer standards. Such API provides no support or a very limited - support to new standards and/or new hardware. - - 3. Nowadays, most frontends support multiple delivery systems. - Only with DVB API version 5 calls it is possible to switch between - the multiple delivery systems supported by a frontend. - - 4. DVB API version 5 is also called *S2API*, as the first - new standard added to it was DVB-S2. - -**Example**: in order to set the hardware to tune into a DVB-C channel -at 651 kHz, modulated with 256-QAM, FEC 3/4 and symbol rate of 5.217 -Mbauds, those properties should be sent to -:ref:`FE_SET_PROPERTY <FE_GET_PROPERTY>` ioctl: - - :ref:`DTV_DELIVERY_SYSTEM <DTV-DELIVERY-SYSTEM>` = SYS_DVBC_ANNEX_A - - :ref:`DTV_FREQUENCY <DTV-FREQUENCY>` = 651000000 - - :ref:`DTV_MODULATION <DTV-MODULATION>` = QAM_256 - - :ref:`DTV_INVERSION <DTV-INVERSION>` = INVERSION_AUTO - - :ref:`DTV_SYMBOL_RATE <DTV-SYMBOL-RATE>` = 5217000 - - :ref:`DTV_INNER_FEC <DTV-INNER-FEC>` = FEC_3_4 - - :ref:`DTV_TUNE <DTV-TUNE>` - -The code that would that would do the above is show in -:ref:`dtv-prop-example`. - -.. code-block:: c - :caption: Example: Setting digital TV frontend properties - :name: dtv-prop-example - - #include <stdio.h> - #include <fcntl.h> - #include <sys/ioctl.h> - #include <linux/dvb/frontend.h> - - static struct dtv_property props[] = { - { .cmd = DTV_DELIVERY_SYSTEM, .u.data = SYS_DVBC_ANNEX_A }, - { .cmd = DTV_FREQUENCY, .u.data = 651000000 }, - { .cmd = DTV_MODULATION, .u.data = QAM_256 }, - { .cmd = DTV_INVERSION, .u.data = INVERSION_AUTO }, - { .cmd = DTV_SYMBOL_RATE, .u.data = 5217000 }, - { .cmd = DTV_INNER_FEC, .u.data = FEC_3_4 }, - { .cmd = DTV_TUNE } - }; - - static struct dtv_properties dtv_prop = { - .num = 6, .props = props - }; - - int main(void) - { - int fd = open("/dev/dvb/adapter0/frontend0", O_RDWR); - - if (!fd) { - perror ("open"); - return -1; - } - if (ioctl(fd, FE_SET_PROPERTY, &dtv_prop) == -1) { - perror("ioctl"); - return -1; - } - printf("Frontend set\\n"); - return 0; - } - -.. attention:: While it is possible to directly call the Kernel code like the - above example, it is strongly recommended to use - `libdvbv5 <https://linuxtv.org/docs/libdvbv5/index.html>`__, as it - provides abstraction to work with the supported digital TV standards and - provides methods for usual operations like program scanning and to - read/write channel descriptor files. - -.. toctree:: - :maxdepth: 1 - - fe_property_parameters - frontend-stat-properties - frontend-property-terrestrial-systems - frontend-property-cable-systems - frontend-property-satellite-systems - frontend-header |