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A FreeBSD driver for some DekTec ASI boards (DTA-140, DTA-145, DTA-2145).
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A FreeBSD driver for some DekTec ASI boards (DTA-140, DTA-145, DTA-2145). It is compatible with FreeBSD 7.x, 8.x, 9.x and possibly 10.x (untested).

  • dektec.c - the actual device driver code
  • dektec.h - lots of IOCTL codes used in the driver
  • Dta1xxCodes.h - codes and constants from DekTec
  • Dta1xxRegs.h - use to include GenRegs.h, RxRegs.h and TxRegs.h.
  • GenRegs.h - definitions related to the generic control register, from DekTec, adapted to FreeBSD
  • RxRegs.h - definitions related to the RX control register, from DekTec, adapted to FreeBSD
  • TxRegs.h - definitions related to the TX control register, from DekTec, adapted to FreeBSD
  • Plx905x.h - constants for the PLX 905x PCI controller chip (9056 in our case).

Basically, the .h files are the same as the headers distributed with the DekTec driver for Linux, minus a few adaptations related to FreeBSD (mostly busdma(9) and bus_space(9)).

Pretty much everything happens in dektec.c. The driver is not compatible with DekTec's DTAPI but it supports a read/write interface with polling.

To understand what is going on you will need at least some of the following:

Bonus items:

  • The DTA-140 data sheet, DVB/ASI Input+Output Adapter for PCI Bus, which will provide a broad description of the DTA-140 operations.

  • A copy of ISO/IEC 13818 Part 1 could help when developing userland software.

  • If you are using DVB, the relevant ETSI standards that you can grab at

To actually try things out:

  • An ASI source and/or ASI analyzer to handle actual streams.

  • A valid MPEG2 transport stream to test the output functions. You can make one with ffmpeg or grab it from a TV decoder that supports TS recording.

How to install

Run make install from the project directory:

# make install
install -o root -g wheel -m 555 dektec.ko /boot/kernel
kldxref /boot/kernel

To clean up after building:

# make clean cleandepend

Remember to do this when you switch architecture while using the same source tree (i.e. when building from i386 and amd64 boxes over a NFS share).

To load or unload the locally compiled driver:

# make load


# make unload

To load or unload the installed driver:

# kldload dektec


# kldunload dektec

To uninstall the driver:

# rm -f /boot/kernel/dektec.ko
# kldxref /boot/kernel

To load at every boot, add dektec_load="YES" to your /boot/loader.conf.

You might also create a package to be used with pkg_add and pkg_delete. Be sure to use matching FreeBSD versions when deploying binaries.

Bugs / gotchas

  • None if you use it correctly :) uptimes of years have been observed in production (v1.0.0), but the range of operations performed by the client software is quite narrow so you'd better test everything carefully in your environment.

  • Only 188-byte packet are supported.

  • Lots of boards are missing, but I can only support the models that I am actually using. The DTA-140 could be probably considered legacy and you will not be able to order it anymore. Lots of code is related to the handling of this board, which was the first to be implemented.

  • SDI operations are not supported.

  • USB devices are not supported (not sure how much work it could be).

  • You might have noticed that there's no documentation.

  • Lots of constants may be unused, but you'd better keep them for future use.

Version history

  • v1.0.0: Initial import from production code
  • v1.1.0: General cleanup
  • v1.2.1: Locking improvements
  • v1.2.2: Fixed call to bus_dmamap_load (BUS_DMA_NOWAIT).


  • Cleanup dumb assumptions in desc_dmamap_cb.

  • Use bus_dmamap_load_uio.

  • Carefully review the dmamap callbacks for edge cases.

  • Split the TX and RX channels into multiple devices. Then we should be able to add support for input- and output-only boards with multiple channels.

  • Let userland software configure the programmable input/output channel on the DTA-145. Right now it is hardcoded as input.

  • Add a few sysctl values to set the default parameters. This could be used to make streams accessible to shell scripts / pipes and to use netcat or ssh as a transport.

  • Add support for 208-byte packets.

  • Do something useful with the led, possibly from userland.

  • Do something interesting with DTrace.

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