Is writing usb devices as files (via /dev/ugen*) supported in FreeBSD?

[Hans Petter Selasky]

On 12/07/14 23:52, Torfinn Ingolfsen wrote:
> Hello,
> Question: is writing to the device file (/dev/ugenX) with normal file calls supposed to work in FreeBSD?
> (as in "everything is a file" in unix-like operating systems)
>
> Background: I recently got a usb label printer for cheap: a Dymo LabelManager PnP[1]. I found the dymoprint[2] Python script, which works fairly well on Linux.
> It works (AFAICT) by reading / writing the usb device as a regular file, via the device file.
> You have to use usb_modeswitch[3] on the printer first, of course.

Hi,

/dev/ugenX is not a stream. You should either consider using libusb or 
/dev/ulptX .

If it is supposed to work with those devices, you should postfix the 
endpoint number:

/dev/usb/3.4.z

--HPS

>
> Since we have all tools available on FreeBSD, I tried the setup on my FreeBSD workstation, which currently runs FreeBSD 9.3-stable:
> tingo at kg-core1$ uname -a
> FreeBSD kg-core1.kg4.no 9.3-STABLE FreeBSD 9.3-STABLE #0 r273918: Fri Oct 31 22:52:44 CET 2014     root at kg-core1.kg4.no:/usr/obj/usr/src/sys/GENERIC  amd64
>
> The detection code in the dymoprint script doesn't work on FreeBSD, but setting the correct device via DEV_NODE in the script works:
> tingo at kg-core1$ grep ^DEV_NODE dymoprint2
> DEV_NODE       = "/dev/ugen3.4"
>
> But when I run the script I just get an IO error:
> root at kg-core1# python dymoprint2 test
> Traceback (most recent call last):
>    File "dymoprint2", line 313, in <module>
>      main()
>    File "dymoprint2", line 309, in main
>      lm.printLabel(labelmatrix, dottab)
>    File "dymoprint2", line 183, in printLabel
>      response = self.sendCommand()
>    File "dymoprint2", line 80, in sendCommand
>      responseBin = self.dev.read(8)
> IOError: [Errno 5] Input/output error
>
>
> References:
> 1) http://global.dymo.com/ieIE/Products/LabelManager_PnP.html
> 2) http://sbronner.com/dymoprint/
> 3) http://www.draisberghof.de/usb_modeswitch/
>