| b.liu | e958203 | 2025-04-17 19:18:16 +0800 | [diff] [blame] | 1 | .. Permission is granted to copy, distribute and/or modify this |
| 2 | .. document under the terms of the GNU Free Documentation License, |
| 3 | .. Version 1.1 or any later version published by the Free Software |
| 4 | .. Foundation, with no Invariant Sections, no Front-Cover Texts |
| 5 | .. and no Back-Cover Texts. A copy of the license is included at |
| 6 | .. Documentation/media/uapi/fdl-appendix.rst. |
| 7 | .. |
| 8 | .. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections |
| 9 | |
| 10 | .. _FE_SET_TONE: |
| 11 | |
| 12 | ***************** |
| 13 | ioctl FE_SET_TONE |
| 14 | ***************** |
| 15 | |
| 16 | Name |
| 17 | ==== |
| 18 | |
| 19 | FE_SET_TONE - Sets/resets the generation of the continuous 22kHz tone. |
| 20 | |
| 21 | |
| 22 | Synopsis |
| 23 | ======== |
| 24 | |
| 25 | .. c:function:: int ioctl( int fd, FE_SET_TONE, enum fe_sec_tone_mode tone ) |
| 26 | :name: FE_SET_TONE |
| 27 | |
| 28 | |
| 29 | Arguments |
| 30 | ========= |
| 31 | |
| 32 | ``fd`` |
| 33 | File descriptor returned by :ref:`open() <frontend_f_open>`. |
| 34 | |
| 35 | ``tone`` |
| 36 | an integer enumered value described at :c:type:`fe_sec_tone_mode` |
| 37 | |
| 38 | |
| 39 | Description |
| 40 | =========== |
| 41 | |
| 42 | This ioctl is used to set the generation of the continuous 22kHz tone. |
| 43 | This call requires read/write permissions. |
| 44 | |
| 45 | Usually, satellite antenna subsystems require that the digital TV device |
| 46 | to send a 22kHz tone in order to select between high/low band on some |
| 47 | dual-band LNBf. It is also used to send signals to DiSEqC equipment, but |
| 48 | this is done using the DiSEqC ioctls. |
| 49 | |
| 50 | .. attention:: If more than one device is connected to the same antenna, |
| 51 | setting a tone may interfere on other devices, as they may lose the |
| 52 | capability of selecting the band. So, it is recommended that applications |
| 53 | would change to SEC_TONE_OFF when the device is not used. |
| 54 | |
| 55 | |
| 56 | Return Value |
| 57 | ============ |
| 58 | |
| 59 | On success 0 is returned. |
| 60 | |
| 61 | On error -1 is returned, and the ``errno`` variable is set |
| 62 | appropriately. |
| 63 | |
| 64 | Generic error codes are described at the |
| 65 | :ref:`Generic Error Codes <gen-errors>` chapter. |