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diff --git a/dvb-spec/dvbapi/frontend.tex b/dvb-spec/dvbapi/frontend.tex new file mode 100644 index 000000000..9ae8a343e --- /dev/null +++ b/dvb-spec/dvbapi/frontend.tex @@ -0,0 +1,674 @@ +\devsec{DVB Frontend API} + +The DVB frontend device controls the tuner and DVB demodulator hardware. +It can be accessed through \texttt{/dev/dvb/adapter0/frontend0}. +Data types and and ioctl definitions can be accessed by including +\texttt{linux/dvb/frontend.h} in your application. + +DVB frontends come in three varieties: DVB-S (satellite), DVB-C (cable) +and DVB-T (terrestrial). Transmission via the internet (DVB-IP) is +not yet handled by this API but a future extension is possible. +For DVB-S the frontend device also supports satellite equipment control +(SEC) via DiSEqC and V-SEC protocols. The DiSEqC (digital SEC) specification +is available from Eutelsat \texttt{http://www.eutelsat.org/}. + +Note that the DVB API may also be used for MPEG decoder-only PCI cards, +in which case there exists no frontend device. + +\devsubsec{Frontend Data Types} + +\devsubsubsec{frontend type} +\label{frontendtype} + +For historical reasons frontend types are named after the +type of modulation used in transmission. + +\begin{verbatim} +typedef enum fe_type { + FE_QPSK, /* DVB-S */ + FE_QAM, /* DVB-C */ + FE_OFDM /* DVB-T */ +} fe_type_t; +\end{verbatim} + +\devsubsubsec{frontend capabilities} +\label{frontendcaps} + +Capabilities describe what a frontend can do. Some capabilities +can only be supported for a specific frontend type. + +\begin{verbatim} +typedef enum fe_caps { + FE_IS_STUPID = 0, + FE_CAN_INVERSION_AUTO = 0x1, + FE_CAN_FEC_1_2 = 0x2, + FE_CAN_FEC_2_3 = 0x4, + FE_CAN_FEC_3_4 = 0x8, + FE_CAN_FEC_4_5 = 0x10, + FE_CAN_FEC_5_6 = 0x20, + FE_CAN_FEC_6_7 = 0x40, + FE_CAN_FEC_7_8 = 0x80, + FE_CAN_FEC_8_9 = 0x100, + FE_CAN_FEC_AUTO = 0x200, + FE_CAN_QPSK = 0x400, + FE_CAN_QAM_16 = 0x800, + FE_CAN_QAM_32 = 0x1000, + FE_CAN_QAM_64 = 0x2000, + FE_CAN_QAM_128 = 0x4000, + FE_CAN_QAM_256 = 0x8000, + FE_CAN_QAM_AUTO = 0x10000, + FE_CAN_TRANSMISSION_MODE_AUTO = 0x20000, + FE_CAN_BANDWIDTH_AUTO = 0x40000, + FE_CAN_GUARD_INTERVAL_AUTO = 0x80000, + FE_CAN_HIERARCHY_AUTO = 0x100000, + FE_CAN_MUTE_TS = 0x80000000, + FE_CAN_CLEAN_SETUP = 0x40000000 +} fe_caps_t; +\end{verbatim} + +\devsubsubsec{frontend information} +\label{frontendinfo} + +Information about the frontend ca be queried with +FE\_GET\_INFO (\ref{fegetinfo}). + +\begin{verbatim} +struct dvb_frontend_info { + char name[128]; + fe_type_t type; + uint32_t frequency_min; + uint32_t frequency_max; + uint32_t frequency_stepsize; + uint32_t frequency_tolerance; + uint32_t symbol_rate_min; + uint32_t symbol_rate_max; + uint32_t symbol_rate_tolerance; /* ppm */ + uint32_t notifier_delay; /* ms */ + fe_caps_t caps; +}; +\end{verbatim} + +\devsubsubsec{diseqc master command} +\label{diseqcmastercmd} + +A message sent from the frontend to DiSEqC capable equipment. + +\begin{verbatim} +struct dvb_diseqc_master_cmd { + uint8_t msg [6]; /* { framing, address, command, data[3] } */ + uint8_t msg_len; /* valid values are 3...6 */ +}; +\end{verbatim} + +\devsubsubsec{diseqc slave reply} +\label{diseqcslavereply} + +A reply to the frontend from DiSEqC 2.0 capable equipment. + +\begin{verbatim} +struct dvb_diseqc_slave_reply { + uint8_t msg [4]; /* { framing, data [3] } */ + uint8_t msg_len; /* valid values are 0...4, 0 means no msg */ + int timeout; /* return from ioctl after timeout ms with */ +}; /* errorcode when no message was received */ +\end{verbatim} + +\devsubsubsec{SEC voltage} +\label{secvoltage} + +The voltage is usually used with non-DiSEqC capable LNBs to +switch the polarzation (horizontal/vertical). +When using DiSEqC epuipment this voltage has to be switched consistently +to the DiSEqC commands as described in the DiSEqC spec. + +\begin{verbatim} +typedef enum fe_sec_voltage { + SEC_VOLTAGE_13, + SEC_VOLTAGE_18 +} fe_sec_voltage_t; +\end{verbatim} + +\devsubsubsec{SEC continuous tone} +\label{sectone} + +The continous 22KHz tone is usually used with non-DiSEqC capable LNBs to +switch the high/low band of a dual-band LNB. +When using DiSEqC epuipment this voltage has to be switched consistently +to the DiSEqC commands as described in the DiSEqC spec. + +\begin{verbatim} +typedef enum fe_sec_tone_mode { + SEC_TONE_ON, + SEC_TONE_OFF +} fe_sec_tone_mode_t; +\end{verbatim} + +\devsubsubsec{SEC tone burst} +\label{sectoneburst} + +The 22KHz tone burst is usually used with non-DiSEqC capable +switches to select between two connected LNBs/satellites. +When using DiSEqC epuipment this voltage has to be switched consistently +to the DiSEqC commands as described in the DiSEqC spec. + +\begin{verbatim} +typedef enum fe_sec_mini_cmd { + SEC_MINI_A, + SEC_MINI_B +} fe_sec_mini_cmd_t; +\end{verbatim} + + +\devsubsubsec{frontend status} +\label{frontendstatus} + +Several functions of the frontend device use the fe\_status data +type defined by +\begin{verbatim} +typedef enum fe_status { + FE_HAS_SIGNAL = 0x01, /* found something above the noise level */ + FE_HAS_CARRIER = 0x02, /* found a DVB signal */ + FE_HAS_VITERBI = 0x04, /* FEC is stable */ + FE_HAS_SYNC = 0x08, /* found sync bytes */ + FE_HAS_LOCK = 0x10, /* everything's working... */ + FE_TIMEDOUT = 0x20, /* no lock within the last ~2 seconds */ + FE_REINIT = 0x40 /* frontend was reinitialized, */ +} fe_status_t; /* application is recommned to reset */ +\end{verbatim} +to indicate the current state and/or state changes of +the frontend hardware. + + +\devsubsubsec{frontend parameters} +\label{frontendparameters} + +The kind of parameters passed to the frontend device for tuning +depend on the kind of hardware you are using. +All kinds of parameters are combined as a union in the +FrontendParameters structure: +\begin{verbatim} +struct dvb_frontend_parameters { + uint32_t frequency; /* (absolute) frequency in Hz for QAM/OFDM */ + /* intermediate frequency in kHz for QPSK */ + fe_spectral_inversion_t inversion; + union { + struct dvb_qpsk_parameters qpsk; + struct dvb_qam_parameters qam; + struct dvb_ofdm_parameters ofdm; + } u; +}; +\end{verbatim} + +For satellite QPSK frontends you have to use the \verb|QPSKParameters| member +defined by +\begin{verbatim} +struct dvb_qpsk_parameters { + uint32_t symbol_rate; /* symbol rate in Symbols per second */ + fe_code_rate_t fec_inner; /* forward error correction (see above) */ +}; +\end{verbatim} +for cable QAM frontend you use the \verb|QAMParameters| structure +\begin{verbatim} +struct dvb_qam_parameters { + uint32_t symbol_rate; /* symbol rate in Symbols per second */ + fe_code_rate_t fec_inner; /* forward error correction (see above) */ + fe_modulation_t modulation; /* modulation type (see above) */ +}; +\end{verbatim} +DVB-T frontends are supported by the \verb|OFDMParamters| structure +\begin{verbatim} +struct dvb_ofdm_parameters { + fe_bandwidth_t bandwidth; + fe_code_rate_t code_rate_HP; /* high priority stream code rate */ + fe_code_rate_t code_rate_LP; /* low priority stream code rate */ + fe_modulation_t constellation; /* modulation type (see above) */ + fe_transmit_mode_t transmission_mode; + fe_guard_interval_t guard_interval; + fe_hierarchy_t hierarchy_information; +}; +\end{verbatim} + +In the case of QPSK frontends the \verb|Frequency| field specifies the +intermediate frequency, i.e. the offset which is effectively added to the +local oscillator frequency (LOF) of the LNB. +The intermediate frequency has to be specified in units of kHz. +For QAM and OFDM frontends the Frequency specifies the absolute frequency +and is given in Hz. + +The Inversion field can take one of these values: +\begin{verbatim} +typedef enum fe_spectral_inversion { + INVERSION_OFF, + INVERSION_ON, + INVERSION_AUTO +} fe_spectral_inversion_t; +\end{verbatim} +It indicates if spectral inversion should be presumed or not. +In the automatic setting (\verb|INVERSION_AUTO|) the hardware will +try to figure out the correct setting by itself. + +\noindent +The possible values for the \verb|FEC_inner| field are +\begin{verbatim} +typedef enum fe_code_rate { + FEC_NONE = 0, + FEC_1_2, + FEC_2_3, + FEC_3_4, + FEC_4_5, + FEC_5_6, + FEC_6_7, + FEC_7_8, + FEC_8_9, + FEC_AUTO +} fe_code_rate_t; +\end{verbatim} +which correspond to error correction rates of 1/2, 2/3, etc., +no error correction or auto detection. + +\noindent +For cable and terrestrial frontends (QAM and OFDM) one also has to +specify the quadrature modulation mode which can be one of the following: +\begin{verbatim} +typedef enum fe_modulation { + QPSK, + QAM_16, + QAM_32, + QAM_64, + QAM_128, + QAM_256, + QAM_AUTO +} fe_modulation_t; +\end{verbatim} + +Finally, there are several more parameters for OFDM: +\begin{verbatim} +typedef enum fe_transmit_mode { + TRANSMISSION_MODE_2K, + TRANSMISSION_MODE_8K, + TRANSMISSION_MODE_AUTO +} fe_transmit_mode_t; +\end{verbatim} + +\begin{verbatim} +typedef enum fe_bandwidth { + BANDWIDTH_8_MHZ, + BANDWIDTH_7_MHZ, + BANDWIDTH_6_MHZ, + BANDWIDTH_AUTO +} fe_bandwidth_t; +\end{verbatim} + +\begin{verbatim} +typedef enum fe_guard_interval { + GUARD_INTERVAL_1_32, + GUARD_INTERVAL_1_16, + GUARD_INTERVAL_1_8, + GUARD_INTERVAL_1_4, + GUARD_INTERVAL_AUTO +} fe_guard_interval_t; +\end{verbatim} + +\begin{verbatim} +typedef enum fe_hierarchy { + HIERARCHY_NONE, + HIERARCHY_1, + HIERARCHY_2, + HIERARCHY_4, + HIERARCHY_AUTO +} fe_hierarchy_t; +\end{verbatim} + + +\devsubsubsec{frontend events} +\label{frontendevents} + +\begin{verbatim} +struct dvb_frontend_event { + fe_status_t status; + struct dvb_frontend_parameters parameters; +}; +\end{verbatim} + +\clearpage + + +\devsubsec{Frontend Function Calls} + +\function{open()}{ + int open(const char *deviceName, int flags);}{ + This system call opens a named frontend device (/dev/dvb/adapter0/frontend0) + for subsequent use. Usually the first thing to do after a successful open + is to find out the frontend type with FE\_GET\_INFO. + + The device can be opened in read-only mode, which only allows + monitoring of device status and statistics, or read/write mode, which allows + any kind of use (e.g. performing tuning operations.) + + In a system with multiple front-ends, it is usually the case that multiple + devices cannot be open in read/write mode simultaneously. As long as a + front-end device is opened in read/write mode, other open() calls in + read/write mode will either fail or block, depending on whether + non-blocking or blocking mode was specified. + A front-end device opened in blocking mode can later be put into non-blocking + mode (and vice versa) using the F\_SETFL command of the fcntl system call. + This is a standard system call, documented in the Linux manual page for fcntl. + When an open() call has succeeded, the device will be ready for use in the + specified mode. This implies that the corresponding hardware is powered up, + and that other front-ends may have been powered down to make that possible. + + }{ + const char *deviceName & Name of specific video device.\\ + int flags & A bit-wise OR of the following flags:\\ + & \hspace{1em} O\_RDONLY read-only access\\ + & \hspace{1em} O\_RDWR read/write access\\ + & \hspace{1em} O\_NONBLOCK open in non-blocking mode \\ + & \hspace{1em} (blocking mode is the default)\\ + }{ + ENODEV & Device driver not loaded/available.\\ + EINTERNAL & Internal error.\\ + EBUSY & Device or resource busy.\\ + EINVAL & Invalid argument.\\ +} + +\function{close()}{ + int close(int fd);}{ + This system call closes a previously opened front-end device. + After closing a front-end device, its corresponding hardware might be + powered down automatically. + }{ + int fd & File descriptor returned by a previous call to open().\\ + }{ + EBADF & fd is not a valid open file descriptor.\\ +} + +\ifunction{FE\_READ\_STATUS}{ + int ioctl(int fd, int request = FE\_READ\_STATUS, fe\_status\_t *status);}{ + This ioctl call returns status information about the front-end. + This call only requires read-only access to the device. + }{ + int fd & File descriptor returned by a previous call to open().\\ + int request & Equals FE\_READ\_STATUS for this command.\\ + struct fe\_status\_t *status & Points to the location where the front-end + status word is to be stored. + }{ + EBADF& fd is not a valid open file descriptor.\\ + EFAULT& status points to invalid address.\\ +} + +\ifunction{FE\_READ\_BER}{ + int ioctl(int fd, int request = FE\_READ\_BER, uint32\_t *ber);}{ + This ioctl call returns the bit error rate for the signal currently + received/demodulated by the front-end. For this command, read-only access + to the device is sufficient. + }{ + int fd & File descriptor returned by a previous call to open().\\ + int request & Equals FE\_READ\_BER for this command.\\ + uint32\_t *ber & The bit error rate is stored into *ber.\\ + }{ + EBADF& fd is not a valid open file descriptor.\\ + EFAULT& ber points to invalid address.\\ + ENOSIGNAL& There is no signal, thus no meaningful bit error + rate. Also returned if the front-end is not turned on.\\ + ENOSYS& Function not available for this device. +} + +\ifunction{FE\_READ\_SNR}{ + int ioctl(int fd, int request = FE\_READ\_SNR, int16\_t *snr);}{ + This ioctl call returns the signal-to-noise ratio for the signal currently + received by the front-end. For this command, read-only access to the device + is sufficient. + }{ + int fd & File descriptor returned by a previous call to open().\\ + int request & Equals FE\_READ\_SNR for this command.\\ + int16\_t *snr& The signal-to-noise ratio is stored into *snr.\\ +}{ + EBADF& fd is not a valid open file descriptor.\\ + EFAULT& snr points to invalid address.\\ + ENOSIGNAL& There is no signal, thus no meaningful signal + strength value. Also returned if front-end is not turned on.\\ + ENOSYS& Function not available for this device. +} + +\ifunction{FE\_READ\_SIGNAL\_STRENGTH}{ + int ioctl( int fd, int request = FE\_READ\_SIGNAL\_STRENGTH, int16\_t *strength); +}{ +This ioctl call returns the signal strength value for the signal currently +received by the front-end. For this command, read-only access to the device +is sufficient. +}{ +int fd & File descriptor returned by a previous call to open().\\ +int request & Equals FE\_READ\_SIGNAL\_STRENGTH for this command.\\ +int16\_t *strength & The signal strength value is stored into *strength.\\ +}{ + EBADF& fd is not a valid open file descriptor.\\ + EFAULT& status points to invalid address.\\ + ENOSIGNAL& There is no signal, thus no meaningful signal + strength value. Also returned if front-end is not turned on.\\ + ENOSYS& Function not available for this device. +} + +\ifunction{FE\_READ\_UNCORRECTED\_BLOCKS}{ + int ioctl( int fd, int request = FE\_READ\_UNCORRECTED\_BLOCKS, uint32\_t *ublocks); }{ + This ioctl call returns the number of uncorrected blocks detected by + the device driver during its lifetime. + For meaningful measurements, the increment in + block count during a specific time interval should be calculated. + For this command, read-only access to the device is sufficient.\\ + Note that the counter will wrap to zero after its maximum count has + been reached. +}{ +int fd & File descriptor returned by a previous call to open().\\ +int request & Equals FE\_READ\_UNCORRECTED\_BLOCKS for this command.\\ +uint32\_t *ublocks & The total number of uncorrected blocks seen +by the driver so far. +}{ + EBADF& fd is not a valid open file descriptor.\\ + EFAULT& ublocks points to invalid address.\\ + ENOSYS& Function not available for this device. +} + + +\ifunction{FE\_SET\_FRONTEND}{ + int ioctl(int fd, int request = FE\_SET\_FRONTEND, struct dvb\_frontend\_parameters *p);}{ + This ioctl call starts a tuning operation using specified parameters. + The result of this call will be successful if the parameters were valid and + the tuning could be initiated. + The result of the tuning operation in itself, however, will arrive + asynchronously as an event (see documentation for FE\_GET\_EVENT + and FrontendEvent.) + If a new FE\_SET\_FRONTEND operation is initiated before the previous + one was completed, + the previous operation will be aborted in favor of the new one. + This command requires read/write access to the device. + }{ + int fd & File descriptor returned by a previous call to open().\\ + int request & Equals FE\_SET\_FRONTEND for this command.\\ + struct dvb\_frontend\_parameters *p& Points to parameters for tuning operation.\\ + }{ + EBADF& fd is not a valid open file descriptor.\\ + EFAULT& p points to invalid address.\\ + EINVAL& Maximum supported symbol rate reached.\\ +} + +\ifunction{FE\_GET\_FRONTEND}{ + int ioctl(int fd, int request = FE\_GET\_FRONTEND, struct dvb\_frontend\_parameters *p);}{ + This ioctl call queries the currently effective frontend parameters. + For this command, read-only access to the device is sufficient. + }{ + int fd & File descriptor returned by a previous call to open().\\ + int request & Equals FE\_SET\_FRONTEND for this command.\\ + struct dvb\_frontend\_parameters *p& Points to parameters for tuning operation.\\ + }{ + EBADF& fd is not a valid open file descriptor.\\ + EFAULT& p points to invalid address.\\ + EINVAL& Maximum supported symbol rate reached.\\ +} + +\ifunction{FE\_GET\_EVENT}{ + int ioctl(int fd, int request = QPSK\_GET\_EVENT, struct dvb\_frontend\_event *ev);}{ + This ioctl call returns a frontend event if available. If an event + is not available, the behavior depends on whether the device is in blocking + or non-blocking mode. In the latter case, the call fails immediately with + errno set to EWOULDBLOCK. In the former case, the call blocks until an event + becomes available.\\ + The standard Linux poll() and/or select() system calls can be used with the + device file descriptor to watch for new events. For select(), the file + descriptor should be included in the exceptfds argument, and for poll(), + POLLPRI should be specified as the wake-up condition. + Since the event queue allocated is rather small (room for 8 events), the queue + must be serviced regularly to avoid overflow. If an overflow happens, the + oldest event is discarded from the queue, and an error (EOVERFLOW) occurs + the next time the queue is read. After reporting the error condition in this + fashion, subsequent FE\_GET\_EVENT calls will return events from the queue as + usual.\\ + For the sake of implementation simplicity, this command requires read/write + access to the device. + }{ + int fd & File descriptor returned by a previous call to open().\\ + int request & Equals FE\_GET\_EVENT for this command.\\ + struct dvb\_frontend\_event *ev & Points to the location where the event,\\ + & if any, is to be stored. + }{ + EBADF& fd is not a valid open file descriptor.\\ + EFAULT& ev points to invalid address.\\ + EWOULDBLOCK & There is no event pending, and the device is in + non-blocking mode.\\ + EOVERFLOW &\\ +& Overflow in event queue - one or more events were lost.\\ +} + +\ifunction{FE\_GET\_INFO}{ +\label{fegetinfo} + int ioctl(int fd, int request = FE\_GET\_INFO, struct dvb\_frontend\_info *info);}{ + This ioctl call returns information about the front-end. + This call only requires read-only access to the device. + }{ + int fd & File descriptor returned by a previous call to open().\\ + int request & Equals FE\_GET\_INFO for this command.\\ + struct dvb\_frontend\_info *info & Points to the location where the front-end + information is to be stored. + }{ + EBADF& fd is not a valid open file descriptor.\\ + EFAULT& info points to invalid address.\\ +} + +\ifunction{FE\_DISEQC\_RESET\_OVERLOAD}{ + int ioctl(int fd, int request = FE\_DISEQC\_RESET\_OVERLOAD);}{ + If the bus has been automatically powered off due to power overload, this + ioctl call restores the power to the bus. The call requires read/write + access to the device. + This call has no effect if the device is manually powered off. + Not all DVB adapters support this ioctl. + }{ + int fd & File descriptor returned by a previous call to open().\\ + int request & Equals FE\_DISEQC\_RESET\_OVERLOAD for this command.\\ + }{ + EBADF & fd is not a valid file descriptor.\\ + EPERM & Permission denied (needs read/write access).\\ + EINTERNAL & Internal error in the device driver.\\ +} + + +\ifunction{FE\_DISEQC\_SEND\_MASTER\_CMD}{ +int ioctl(int fd, int request = FE\_DISEQC\_SEND\_MASTER\_CMD, struct dvb\_diseqc\_master\_cmd *cmd);}{ + This ioctl call is used to send a a DiSEqC command.\\ + }{ + int fd & File descriptor returned by a previous call to open().\\ + int request & Equals FE\_DISEQC\_SEND\_MASTER\_CMD for this command.\\ + struct dvb\_diseqc\_master\_cmd *cmd & Pointer to the command to be transmitted.\\ + }{ + EBADF & fd is not a valid file descriptor.\\ + EFAULT & Seq points to an invalid address.\\ + EINVAL & The data structure referred to by seq is invalid in some way.\\ + EPERM & Permission denied (needs read/write access).\\ + EINTERNAL & Internal error in the device driver.\\ +} + +\ifunction{FE\_DISEQC\_RECV\_SLAVE\_REPLY}{ +int ioctl(int fd, int request = FE\_DISEQC\_RECV\_SLAVE\_REPLY, struct dvb\_diseqc\_slave\_reply *reply);}{ +This ioctl call is used to receive reply to a DiSEqC 2.0 command.\\ + }{ + int fd & File descriptor returned by a previous call to open().\\ + int request & Equals FE\_DISEQC\_RECV\_SLAVE\_REPLY for this command.\\ + struct dvb\_diseqc\_slave\_reply *reply & Pointer to the command to be received.\\ + }{ + EBADF & fd is not a valid file descriptor.\\ + EFAULT & Seq points to an invalid address.\\ + EINVAL & The data structure referred to by seq is invalid in some way.\\ + EPERM & Permission denied (needs read/write access).\\ + EINTERNAL & Internal error in the device driver.\\ +} + +\ifunction{FE\_DISEQC\_SEND\_BURST}{ +int ioctl(int fd, int request = FE\_DISEQC\_SEND\_BURST, fe\_sec\_mini\_cmd\_t burst);}{ +This ioctl call is used to send a 22KHz tone burst.\\ + }{ + int fd & File descriptor returned by a previous call to open().\\ + int request & Equals FE\_DISEQC\_SEND\_BURST for this command.\\ + fe\_sec\_mini\_cmd\_t burst & burst A or B.\\ + }{ + EBADF & fd is not a valid file descriptor.\\ + EFAULT & Seq points to an invalid address.\\ + EINVAL & The data structure referred to by seq is invalid in some way.\\ + EPERM & Permission denied (needs read/write access).\\ + EINTERNAL & Internal error in the device driver.\\ +} + + +\ifunction{FE\_SET\_TONE}{ +int ioctl(int fd, int request = FE\_SET\_TONE, fe\_sec\_tone\_mode\_t tone);}{ +This call is used to set the generation of the continuous 22kHz tone. +This call requires read/write permissions. +}{ +int fd & File descriptor returned by a previous call to open().\\ +int request & Equals FE\_SET\_TONE for this command.\\ +fe\_sec\_tone\_mode\_t tone & The requested tone generation mode (on/off).\\ +}{ +ENODEV & Device driver not loaded/available.\\ +EBUSY & Device or resource busy.\\ +EINVAL & Invalid argument.\\ +EPERM & File not opened with read permissions.\\ +EINTERNAL & Internal error in the device driver.\\ +} + + +\ifunction{FE\_SET\_VOLTAGE}{ +int ioctl(int fd, int request = FE\_SET\_VOLTAGE, fe\_sec\_voltage\_t voltage);}{ +This call is used to set the bus voltage. +This call requires read/write permissions. +}{ +int fd & File descriptor returned by a previous call to open().\\ +int request & Equals FE\_SET\_VOLTAGE for this command.\\ +fe\_sec\_voltage\_t voltage & The requested bus voltage.\\ +}{ +ENODEV & Device driver not loaded/available.\\ +EBUSY & Device or resource busy.\\ +EINVAL & Invalid argument.\\ +EPERM & File not opened with read permissions.\\ +EINTERNAL & Internal error in the device driver.\\ +} + +\ifunction{FE\_ENABLE\_HIGH\_LNB\_VOLTAGE}{ +int ioctl(int fd, int request = FE\_ENABLE\_HIGH\_LNB\_VOLTAGE, int high);}{ +If high != 0 enables slightly higher voltages instead of 13/18V +(to compensate for long cables). +This call requires read/write permissions. +Not all DVB adapters support this ioctl. +}{ +int fd & File descriptor returned by a previous call to open().\\ +int request & Equals FE\_SET\_VOLTAGE for this command.\\ +int high & The requested bus voltage.\\ +}{ +ENODEV & Device driver not loaded/available.\\ +EBUSY & Device or resource busy.\\ +EINVAL & Invalid argument.\\ +EPERM & File not opened with read permissions.\\ +EINTERNAL & Internal error in the device driver.\\ +} + + +%%% Local Variables: +%%% mode: latex +%%% TeX-master: "dvbapi" +%%% End: |