Documentation/DocBook/media/dvb/frontend_legacy_api.xml

   1 <section id="frontend_legacy_types">
   2 <title>Frontend Legacy Data Types</title>
   3
   4 <section id="fe-type-t">
   5 <title>Frontend type</title>
   6
   7 <para>For historical reasons, frontend types are named by the type of modulation
   8     used in transmission. The fontend types are given by fe_type_t type, defined as:</para>
   9
  10 <table pgwide="1" frame="none" id="fe-type">
  11 <title>Frontend types</title>
  12 <tgroup cols="3">
  13    &cs-def;
  14    <thead>
  15      <row>
  16        <entry>fe_type</entry>
  17        <entry>Description</entry>
  18        <entry><link linkend="DTV-DELIVERY-SYSTEM">DTV_DELIVERY_SYSTEM</link> equivalent type</entry>
  19      </row>
  20   </thead>
  21   <tbody valign="top">
  22   <row>
  23      <entry id="FE_QPSK"><constant>FE_QPSK</constant></entry>
  24      <entry>For DVB-S standard</entry>
  25      <entry><constant>SYS_DVBS</constant></entry>
  26   </row>
  27   <row>
  28      <entry id="FE_QAM"><constant>FE_QAM</constant></entry>
  29      <entry>For DVB-C annex A standard</entry>
  30      <entry><constant>SYS_DVBC_ANNEX_A</constant></entry>
  31   </row>
  32   <row>
  33      <entry id="FE_OFDM"><constant>FE_OFDM</constant></entry>
  34      <entry>For DVB-T standard</entry>
  35      <entry><constant>SYS_DVBT</constant></entry>
  36   </row>
  37   <row>
  38      <entry id="FE_ATSC"><constant>FE_ATSC</constant></entry>
  39      <entry>For ATSC standard (terrestrial) or for DVB-C Annex B (cable) used in US.</entry>
  40      <entry><constant>SYS_ATSC</constant> (terrestrial) or <constant>SYS_DVBC_ANNEX_B</constant> (cable)</entry>
  41   </row>
  42 </tbody></tgroup></table>
  43
  44 <para>Newer formats like DVB-S2, ISDB-T, ISDB-S and DVB-T2 are not described at the above, as they're
  45 supported via the new <link linkend="FE_GET_PROPERTY">FE_GET_PROPERTY/FE_GET_SET_PROPERTY</link> ioctl's, using the <link linkend="DTV-DELIVERY-SYSTEM">DTV_DELIVERY_SYSTEM</link> parameter.
  46 </para>
  47
  48 <para>In the old days, &dvb-frontend-info; used to contain
  49     <constant>fe_type_t</constant> field to indicate the delivery systems,
  50     filled with either FE_QPSK, FE_QAM, FE_OFDM or FE_ATSC. While this is
  51     still filled to keep backward compatibility, the usage of this
  52     field is deprecated, as it can report just one delivery system, but some
  53     devices support multiple delivery systems. Please use
  54     <link linkend="DTV-ENUM-DELSYS">DTV_ENUM_DELSYS</link> instead.
  55 </para>
  56 <para>On devices that support multiple delivery systems,
  57     &dvb-frontend-info;::<constant>fe_type_t</constant> is filled with the
  58     currently standard, as selected by the last call to
  59     <link linkend="FE_GET_PROPERTY">FE_SET_PROPERTY</link>
  60     using the &DTV-DELIVERY-SYSTEM; property.</para>
  61 </section>
  62
  63 <section id="fe-bandwidth-t">
  64 <title>Frontend bandwidth</title>
  65
  66 <table pgwide="1" frame="none" id="fe-bandwidth">
  67     <title>enum fe_bandwidth</title>
  68     <tgroup cols="2">
  69         &cs-def;
  70         <thead>
  71         <row>
  72             <entry>ID</entry>
  73             <entry>Description</entry>
  74         </row>
  75         </thead>
  76         <tbody valign="top">
  77         <row>
  78             <entry>BANDWIDTH_AUTO</entry>
  79             <entry>Autodetect bandwidth (if supported)</entry>
  80         </row><row>
  81             <entry>BANDWIDTH_1_712_MHZ</entry>
  82             <entry>1.712 MHz</entry>
  83         </row><row>
  84             <entry>BANDWIDTH_5_MHZ</entry>
  85             <entry>5 MHz</entry>
  86         </row><row>
  87             <entry>BANDWIDTH_6_MHZ</entry>
  88             <entry>6 MHz</entry>
  89         </row><row>
  90             <entry>BANDWIDTH_7_MHZ</entry>
  91             <entry>7 MHz</entry>
  92         </row><row>
  93             <entry>BANDWIDTH_8_MHZ</entry>
  94             <entry>8 MHz</entry>
  95         </row><row>
  96             <entry>BANDWIDTH_10_MHZ</entry>
  97             <entry>10 MHz</entry>
  98         </row><row>
  99         </row>
 100         </tbody>
 101     </tgroup>
 102 </table>
 103
 104 </section>
 105
 106 <section id="dvb-frontend-parameters">
 107 <title>frontend parameters</title>
 108 <para>The kind of parameters passed to the frontend device for tuning depend on
 109 the kind of hardware you are using.</para>
 110 <para>The struct <constant>dvb_frontend_parameters</constant> uses an
 111 union with specific per-system parameters. However, as newer delivery systems
 112 required more data, the structure size weren't enough to fit, and just
 113 extending its size would break the existing applications. So, those parameters
 114 were replaced by the usage of <link linkend="FE_GET_PROPERTY">
 115 <constant>FE_GET_PROPERTY/FE_SET_PROPERTY</constant></link> ioctl's. The
 116 new API is flexible enough to add new parameters to existing delivery systems,
 117 and to add newer delivery systems.</para>
 118 <para>So, newer applications should use <link linkend="FE_GET_PROPERTY">
 119 <constant>FE_GET_PROPERTY/FE_SET_PROPERTY</constant></link> instead, in
 120 order to be able to support the newer System Delivery like  DVB-S2, DVB-T2,
 121 DVB-C2, ISDB, etc.</para>
 122 <para>All kinds of parameters are combined as an union in the FrontendParameters structure:
 123 <programlisting>
 124 struct dvb_frontend_parameters {
 125         uint32_t frequency;     /&#x22C6; (absolute) frequency in Hz for QAM/OFDM &#x22C6;/
 126                                 /&#x22C6; intermediate frequency in kHz for QPSK &#x22C6;/
 127         &fe-spectral-inversion-t; inversion;
 128         union {
 129                 struct dvb_qpsk_parameters qpsk;
 130                 struct dvb_qam_parameters  qam;
 131                 struct dvb_ofdm_parameters ofdm;
 132                 struct dvb_vsb_parameters  vsb;
 133         } u;
 134 };
 135 </programlisting></para>
 136 <para>In the case of QPSK frontends the <constant>frequency</constant> field specifies the intermediate
 137 frequency, i.e. the offset which is effectively added to the local oscillator frequency (LOF) of
 138 the LNB. The intermediate frequency has to be specified in units of kHz. For QAM and
 139 OFDM frontends the <constant>frequency</constant> specifies the absolute frequency and is given in Hz.
 140 </para>
 141
 142 <section id="dvb-qpsk-parameters">
 143 <title>QPSK parameters</title>
 144 <para>For satellite QPSK frontends you have to use the <constant>dvb_qpsk_parameters</constant> structure:</para>
 145 <programlisting>
 146  struct dvb_qpsk_parameters {
 147          uint32_t        symbol_rate;  /&#x22C6; symbol rate in Symbols per second &#x22C6;/
 148          fe_code_rate_t  fec_inner;    /&#x22C6; forward error correction (see above) &#x22C6;/
 149  };
 150 </programlisting>
 151 </section>
 152
 153 <section id="dvb-qam-parameters">
 154 <title>QAM parameters</title>
 155 <para>for cable QAM frontend you use the <constant>dvb_qam_parameters</constant> structure:</para>
 156 <programlisting>
 157  struct dvb_qam_parameters {
 158          uint32_t         symbol_rate; /&#x22C6; symbol rate in Symbols per second &#x22C6;/
 159          fe_code_rate_t   fec_inner;   /&#x22C6; forward error correction (see above) &#x22C6;/
 160          &fe-modulation-t;  modulation;  /&#x22C6; modulation type (see above) &#x22C6;/
 161  };
 162 </programlisting>
 163 </section>
 164
 165 <section id="dvb-vsb-parameters">
 166 <title>VSB parameters</title>
 167 <para>ATSC frontends are supported by the <constant>dvb_vsb_parameters</constant> structure:</para>
 168 <programlisting>
 169 struct dvb_vsb_parameters {
 170         &fe-modulation-t; modulation;   /&#x22C6; modulation type (see above) &#x22C6;/
 171 };
 172 </programlisting>
 173 </section>
 174
 175 <section id="dvb-ofdm-parameters">
 176 <title>OFDM parameters</title>
 177 <para>DVB-T frontends are supported by the <constant>dvb_ofdm_parameters</constant> structure:</para>
 178 <programlisting>
 179  struct dvb_ofdm_parameters {
 180          &fe-bandwidth-t;      bandwidth;
 181          fe_code_rate_t      code_rate_HP;  /&#x22C6; high priority stream code rate &#x22C6;/
 182          fe_code_rate_t      code_rate_LP;  /&#x22C6; low priority stream code rate &#x22C6;/
 183          &fe-modulation-t;     constellation; /&#x22C6; modulation type (see above) &#x22C6;/
 184          &fe-transmit-mode-t;  transmission_mode;
 185          fe_guard_interval_t guard_interval;
 186          fe_hierarchy_t      hierarchy_information;
 187  };
 188 </programlisting>
 189 </section>
 190 </section>
 191
 192 <section id="dvb-frontend-event">
 193 <title>frontend events</title>
 194  <programlisting>
 195  struct dvb_frontend_event {
 196          fe_status_t status;
 197          struct dvb_frontend_parameters parameters;
 198  };
 199 </programlisting>
 200  </section>
 201 </section>
 202
 203 <section id="frontend_fcalls">
 204 <title>Frontend Legacy Function Calls</title>
 205
 206 <para>Those functions are defined at DVB version 3. The support is kept in
 207     the kernel due to compatibility issues only. Their usage is strongly
 208     not recommended</para>
 209
 210 <section id="FE_READ_BER">
 211 <title>FE_READ_BER</title>
 212 <para>DESCRIPTION
 213 </para>
 214 <informaltable><tgroup cols="1"><tbody><row><entry
 215  align="char">
 216 <para>This ioctl call returns the bit error rate for the signal currently
 217  received/demodulated by the front-end. For this command, read-only access to
 218  the device is sufficient.</para>
 219 </entry>
 220  </row></tbody></tgroup></informaltable>
 221 <para>SYNOPSIS
 222 </para>
 223 <informaltable><tgroup cols="1"><tbody><row><entry
 224  align="char">
 225 <para>int ioctl(int fd, int request = <link linkend="FE_READ_BER">FE_READ_BER</link>,
 226  uint32_t &#x22C6;ber);</para>
 227 </entry>
 228  </row></tbody></tgroup></informaltable>
 229 <para>PARAMETERS
 230 </para>
 231 <informaltable><tgroup cols="2"><tbody><row><entry
 232  align="char">
 233 <para>int fd</para>
 234 </entry><entry
 235  align="char">
 236 <para>File descriptor returned by a previous call to open().</para>
 237 </entry>
 238  </row><row><entry
 239  align="char">
 240 <para>int request</para>
 241 </entry><entry
 242  align="char">
 243 <para>Equals <link linkend="FE_READ_BER">FE_READ_BER</link> for this command.</para>
 244 </entry>
 245  </row><row><entry
 246  align="char">
 247 <para>uint32_t *ber</para>
 248 </entry><entry
 249  align="char">
 250 <para>The bit error rate is stored into *ber.</para>
 251 </entry>
 252  </row></tbody></tgroup></informaltable>
 253
 254 &return-value-dvb;
 255 </section>
 256
 257 <section id="FE_READ_SNR">
 258 <title>FE_READ_SNR</title>
 259
 260 <para>DESCRIPTION
 261 </para>
 262 <informaltable><tgroup cols="1"><tbody><row><entry
 263  align="char">
 264 <para>This ioctl call returns the signal-to-noise ratio for the signal currently received
 265  by the front-end. For this command, read-only access to the device is sufficient.</para>
 266 </entry>
 267  </row></tbody></tgroup></informaltable>
 268 <para>SYNOPSIS
 269 </para>
 270 <informaltable><tgroup cols="1"><tbody><row><entry
 271  align="char">
 272 <para>int ioctl(int fd, int request = <link linkend="FE_READ_SNR">FE_READ_SNR</link>, uint16_t
 273  &#x22C6;snr);</para>
 274 </entry>
 275  </row></tbody></tgroup></informaltable>
 276 <para>PARAMETERS
 277 </para>
 278 <informaltable><tgroup cols="2"><tbody><row><entry
 279  align="char">
 280 <para>int fd</para>
 281 </entry><entry
 282  align="char">
 283 <para>File descriptor returned by a previous call to open().</para>
 284 </entry>
 285  </row><row><entry
 286  align="char">
 287 <para>int request</para>
 288 </entry><entry
 289  align="char">
 290 <para>Equals <link linkend="FE_READ_SNR">FE_READ_SNR</link> for this command.</para>
 291 </entry>
 292  </row><row><entry
 293  align="char">
 294 <para>uint16_t *snr</para>
 295 </entry><entry
 296  align="char">
 297 <para>The signal-to-noise ratio is stored into *snr.</para>
 298 </entry>
 299  </row></tbody></tgroup></informaltable>
 300
 301 &return-value-dvb;
 302 </section>
 303
 304 <section id="FE_READ_SIGNAL_STRENGTH">
 305 <title>FE_READ_SIGNAL_STRENGTH</title>
 306 <para>DESCRIPTION
 307 </para>
 308 <informaltable><tgroup cols="1"><tbody><row><entry
 309  align="char">
 310 <para>This ioctl call returns the signal strength value for the signal currently received
 311  by the front-end. For this command, read-only access to the device is sufficient.</para>
 312 </entry>
 313  </row></tbody></tgroup></informaltable>
 314 <para>SYNOPSIS
 315 </para>
 316 <informaltable><tgroup cols="1"><tbody><row><entry
 317  align="char">
 318 <para>int ioctl( int fd, int request =
 319  <link linkend="FE_READ_SIGNAL_STRENGTH">FE_READ_SIGNAL_STRENGTH</link>, uint16_t &#x22C6;strength);</para>
 320 </entry>
 321  </row></tbody></tgroup></informaltable>
 322
 323 <para>PARAMETERS
 324 </para>
 325 <informaltable><tgroup cols="2"><tbody><row><entry
 326  align="char">
 327 <para>int fd</para>
 328 </entry><entry
 329  align="char">
 330 <para>File descriptor returned by a previous call to open().</para>
 331 </entry>
 332  </row><row><entry
 333  align="char">
 334 <para>int request</para>
 335 </entry><entry
 336  align="char">
 337 <para>Equals <link linkend="FE_READ_SIGNAL_STRENGTH">FE_READ_SIGNAL_STRENGTH</link> for this
 338  command.</para>
 339 </entry>
 340  </row><row><entry
 341  align="char">
 342 <para>uint16_t *strength</para>
 343 </entry><entry
 344  align="char">
 345 <para>The signal strength value is stored into *strength.</para>
 346 </entry>
 347  </row></tbody></tgroup></informaltable>
 348
 349 &return-value-dvb;
 350 </section>
 351
 352 <section id="FE_READ_UNCORRECTED_BLOCKS">
 353 <title>FE_READ_UNCORRECTED_BLOCKS</title>
 354 <para>DESCRIPTION
 355 </para>
 356 <informaltable><tgroup cols="1"><tbody><row><entry
 357  align="char">
 358 <para>This ioctl call returns the number of uncorrected blocks detected by the device
 359  driver during its lifetime. For meaningful measurements, the increment in block
 360  count during a specific time interval should be calculated. For this command,
 361  read-only access to the device is sufficient.</para>
 362 </entry>
 363  </row><row><entry
 364  align="char">
 365 <para>Note that the counter will wrap to zero after its maximum count has been
 366  reached.</para>
 367 </entry>
 368  </row></tbody></tgroup></informaltable>
 369 <para>SYNOPSIS
 370 </para>
 371 <informaltable><tgroup cols="1"><tbody><row><entry
 372  align="char">
 373 <para>int ioctl( int fd, int request =
 374  <link linkend="FE_READ_UNCORRECTED_BLOCKS">FE_READ_UNCORRECTED_BLOCKS</link>, uint32_t &#x22C6;ublocks);</para>
 375 </entry>
 376  </row></tbody></tgroup></informaltable>
 377 <para>PARAMETERS
 378 </para>
 379 <informaltable><tgroup cols="2"><tbody><row><entry
 380  align="char">
 381 <para>int fd</para>
 382 </entry><entry
 383  align="char">
 384 <para>File descriptor returned by a previous call to open().</para>
 385 </entry>
 386  </row><row><entry
 387  align="char">
 388 <para>int request</para>
 389 </entry><entry
 390  align="char">
 391 <para>Equals <link linkend="FE_READ_UNCORRECTED_BLOCKS">FE_READ_UNCORRECTED_BLOCKS</link> for this
 392  command.</para>
 393 </entry>
 394  </row><row><entry
 395  align="char">
 396 <para>uint32_t *ublocks</para>
 397 </entry><entry
 398  align="char">
 399 <para>The total number of uncorrected blocks seen by the driver
 400  so far.</para>
 401 </entry>
 402  </row></tbody></tgroup></informaltable>
 403
 404 &return-value-dvb;
 405 </section>
 406
 407 <section id="FE_SET_FRONTEND">
 408 <title>FE_SET_FRONTEND</title>
 409 <para>DESCRIPTION
 410 </para>
 411 <informaltable><tgroup cols="1"><tbody><row><entry
 412  align="char">
 413 <para>This ioctl call starts a tuning operation using specified parameters. The result
 414  of this call will be successful if the parameters were valid and the tuning could
 415  be initiated. The result of the tuning operation in itself, however, will arrive
 416  asynchronously as an event (see documentation for <link linkend="FE_GET_EVENT">FE_GET_EVENT</link> and
 417  FrontendEvent.) If a new <link linkend="FE_SET_FRONTEND">FE_SET_FRONTEND</link> operation is initiated before
 418  the previous one was completed, the previous operation will be aborted in favor
 419  of the new one. This command requires read/write access to the device.</para>
 420 </entry>
 421  </row></tbody></tgroup></informaltable>
 422
 423 <para>SYNOPSIS
 424 </para>
 425 <informaltable><tgroup cols="1"><tbody><row><entry
 426  align="char">
 427 <para>int ioctl(int fd, int request = <link linkend="FE_SET_FRONTEND">FE_SET_FRONTEND</link>,
 428  struct dvb_frontend_parameters &#x22C6;p);</para>
 429 </entry>
 430  </row></tbody></tgroup></informaltable>
 431 <para>PARAMETERS
 432 </para>
 433 <informaltable><tgroup cols="2"><tbody><row><entry
 434  align="char">
 435 <para>int fd</para>
 436 </entry><entry
 437  align="char">
 438 <para>File descriptor returned by a previous call to open().</para>
 439 </entry>
 440  </row><row><entry
 441  align="char">
 442 <para>int request</para>
 443 </entry><entry
 444  align="char">
 445 <para>Equals <link linkend="FE_SET_FRONTEND">FE_SET_FRONTEND</link> for this command.</para>
 446 </entry>
 447  </row><row><entry
 448  align="char">
 449 <para>struct
 450  dvb_frontend_parameters
 451  *p</para>
 452 </entry><entry
 453  align="char">
 454 <para>Points to parameters for tuning operation.</para>
 455 </entry>
 456  </row></tbody></tgroup></informaltable>
 457
 458 &return-value-dvb;
 459 <informaltable><tgroup cols="2"><tbody><row><entry
 460  align="char">
 461 <para>EINVAL</para>
 462 </entry><entry
 463  align="char">
 464 <para>Maximum supported symbol rate reached.</para>
 465 </entry>
 466 </row></tbody></tgroup></informaltable>
 467 </section>
 468
 469 <section id="FE_GET_FRONTEND">
 470 <title>FE_GET_FRONTEND</title>
 471 <para>DESCRIPTION
 472 </para>
 473 <informaltable><tgroup cols="1"><tbody><row><entry
 474  align="char">
 475 <para>This ioctl call queries the currently effective frontend parameters. For this
 476  command, read-only access to the device is sufficient.</para>
 477 </entry>
 478  </row></tbody></tgroup></informaltable>
 479
 480 <para>SYNOPSIS
 481 </para>
 482 <informaltable><tgroup cols="1"><tbody><row><entry
 483  align="char">
 484 <para>int ioctl(int fd, int request = <link linkend="FE_GET_FRONTEND">FE_GET_FRONTEND</link>,
 485  struct dvb_frontend_parameters &#x22C6;p);</para>
 486 </entry>
 487  </row></tbody></tgroup></informaltable>
 488
 489 <para>PARAMETERS
 490 </para>
 491 <informaltable><tgroup cols="2"><tbody><row><entry
 492  align="char">
 493 <para>int fd</para>
 494 </entry><entry
 495  align="char">
 496 <para>File descriptor returned by a previous call to open().</para>
 497 </entry>
 498  </row><row><entry
 499  align="char">
 500 <para>int request</para>
 501 </entry><entry
 502  align="char">
 503 <para>Equals <link linkend="FE_SET_FRONTEND">FE_SET_FRONTEND</link> for this command.</para>
 504 </entry>
 505  </row><row><entry
 506  align="char">
 507 <para>struct
 508  dvb_frontend_parameters
 509  *p</para>
 510 </entry><entry
 511  align="char">
 512 <para>Points to parameters for tuning operation.</para>
 513 </entry>
 514  </row></tbody></tgroup></informaltable>
 515
 516 &return-value-dvb;
 517 <informaltable><tgroup cols="2"><tbody><row><entry
 518  align="char">
 519 <para>EINVAL</para>
 520 </entry><entry
 521  align="char">
 522 <para>Maximum supported symbol rate reached.</para>
 523 </entry>
 524  </row></tbody></tgroup></informaltable>
 525
 526 </section>
 527
 528 <section id="FE_GET_EVENT">
 529 <title>FE_GET_EVENT</title>
 530 <para>DESCRIPTION
 531 </para>
 532 <informaltable><tgroup cols="1"><tbody><row><entry
 533  align="char">
 534 <para>This ioctl call returns a frontend event if available. If an event is not
 535  available, the behavior depends on whether the device is in blocking or
 536  non-blocking mode. In the latter case, the call fails immediately with errno
 537  set to EWOULDBLOCK. In the former case, the call blocks until an event
 538  becomes available.</para>
 539 </entry>
 540  </row><row><entry
 541  align="char">
 542 <para>The standard Linux poll() and/or select() system calls can be used with the
 543  device file descriptor to watch for new events. For select(), the file descriptor
 544  should be included in the exceptfds argument, and for poll(), POLLPRI should
 545  be specified as the wake-up condition. Since the event queue allocated is
 546  rather small (room for 8 events), the queue must be serviced regularly to avoid
 547  overflow. If an overflow happens, the oldest event is discarded from the queue,
 548  and an error (EOVERFLOW) occurs the next time the queue is read. After
 549  reporting the error condition in this fashion, subsequent
 550  <link linkend="FE_GET_EVENT">FE_GET_EVENT</link>
 551  calls will return events from the queue as usual.</para>
 552 </entry>
 553  </row><row><entry
 554  align="char">
 555 <para>For the sake of implementation simplicity, this command requires read/write
 556  access to the device.</para>
 557 </entry>
 558  </row></tbody></tgroup></informaltable>
 559
 560 <para>SYNOPSIS
 561 </para>
 562 <informaltable><tgroup cols="1"><tbody><row><entry
 563  align="char">
 564 <para>int ioctl(int fd, int request = QPSK_GET_EVENT,
 565  struct dvb_frontend_event &#x22C6;ev);</para>
 566 </entry>
 567  </row></tbody></tgroup></informaltable>
 568
 569 <para>PARAMETERS
 570 </para>
 571 <informaltable><tgroup cols="2"><tbody><row><entry
 572  align="char">
 573 <para>int fd</para>
 574 </entry><entry
 575  align="char">
 576 <para>File descriptor returned by a previous call to open().</para>
 577 </entry>
 578  </row><row><entry
 579  align="char">
 580 <para>int request</para>
 581 </entry><entry
 582  align="char">
 583 <para>Equals <link linkend="FE_GET_EVENT">FE_GET_EVENT</link> for this command.</para>
 584 </entry>
 585  </row><row><entry
 586  align="char">
 587 <para>struct
 588  dvb_frontend_event
 589  *ev</para>
 590 </entry><entry
 591  align="char">
 592 <para>Points to the location where the event,</para>
 593 </entry>
 594  </row><row><entry
 595  align="char">
 596 </entry><entry
 597  align="char">
 598 <para>if any, is to be stored.</para>
 599 </entry>
 600  </row></tbody></tgroup></informaltable>
 601
 602 &return-value-dvb;
 603 <informaltable><tgroup cols="2"><tbody><row><entry
 604  align="char">
 605 <para>EWOULDBLOCK</para>
 606 </entry><entry
 607  align="char">
 608 <para>There is no event pending, and the device is in
 609  non-blocking mode.</para>
 610 </entry>
 611  </row><row><entry
 612  align="char">
 613 <para>EOVERFLOW</para>
 614 </entry><entry
 615  align="char">
 616 <para>Overflow in event queue - one or more events were lost.</para>
 617 </entry>
 618 </row></tbody></tgroup></informaltable>
 619 </section>
 620
 621 <section id="FE_DISHNETWORK_SEND_LEGACY_CMD">
 622         <title>FE_DISHNETWORK_SEND_LEGACY_CMD</title>
 623 <para>DESCRIPTION</para>
 624 <informaltable><tgroup cols="1"><tbody><row>
 625 <entry align="char">
 626 <para>WARNING: This is a very obscure legacy command, used only at stv0299 driver. Should not be used on newer drivers.</para>
 627 <para>It provides a non-standard method for selecting Diseqc voltage on the frontend, for Dish Network legacy switches.</para>
 628 <para>As support for this ioctl were added in 2004, this means that such dishes were already legacy in 2004.</para>
 629 </entry>
 630 </row></tbody></tgroup></informaltable>
 631
 632 <para>SYNOPSIS</para>
 633 <informaltable><tgroup cols="1"><tbody><row>
 634 <entry align="char">
 635 <para>int ioctl(int fd, int request =
 636         <link linkend="FE_DISHNETWORK_SEND_LEGACY_CMD">FE_DISHNETWORK_SEND_LEGACY_CMD</link>, unsigned long cmd);</para>
 637 </entry>
 638 </row></tbody></tgroup></informaltable>
 639
 640 <para>PARAMETERS</para>
 641 <informaltable><tgroup cols="2"><tbody><row>
 642 <entry align="char">
 643         <para>unsigned long cmd</para>
 644 </entry>
 645 <entry align="char">
 646 <para>
 647 sends the specified raw cmd to the dish via DISEqC.
 648 </para>
 649 </entry>
 650  </row></tbody></tgroup></informaltable>
 651
 652 &return-value-dvb;
 653 </section>
 654
 655 </section>