Good morning,
We are trying to control two USRP B205i simultaneously on the same device (an
ODROID XU4 running Ubuntu 16.04 minimal).
Our goal is to launch two instances of our software on system power up (without
the need of the user logging in into the OS), each one of them running a
different USRP front-end selected by its unique serial. So we have configured
them as 3 cron tasks:
@reboot uhd_find_devices > /home/user/log/uhd.log 2>&1
@reboot /usr/bin/screen -dmSL first_usrp /home/user/myapp -s settings1.ini
@reboot /usr/bin/screen -dmSL second_usrp /home/user/myapp -s settings2.ini
The first line will store in a log file the result of calling uhd_find_devices,
just to check that both front-ends are being detected.
The other lines will run myapp instances with different settings using screen
command.
This system design was tested using a laptop (instead of the ODROID, using
Ubuntu 16.04 desktop edition) and worked successfully. Nevertheless, when
working over the ODROID, if I check screen log files, my first_usrp session
starts correctly and continues working continuously. On the other hand, my
second_usrp session throws an error and myapp terminates:
UHD Error:
The receive packet handler caught an exception.
RuntimeError: usb rx6 transfer status: LIBUSB_TRANSFER_ERROR
terminate called after throwing an instance of 'std::runtime_error'
what(): Receiver error: ERROR_CODE_BAD_PACKET
Please note that this does not mean that second_usrp session is the one which
fails always. In other occasions the one which fails is the first one. It just
seems that it is not possible to handle both USRPs at the same time. Also,
while typically this error happens for one of the USRPs just after being
initialized in our code, in some cases it even runs smoothly for both USRPs for
a while (less than 10 seconds) until the error is thrown anyway for one of the
front-ends.
My first though was that this is a power problem, with the ODROID not being
able to supply enough amperage to the USRPs. Although I couldn't find the
information about USRP 205-I power consumption, this doesn't seem to be the
problem since I tested using a power supply up to 20A and consumption did never
go north of 3-3.2A and the problem appeared again.
I also considered CPU usage to be a problem, but after setting exclusive cores
to each instance the problem persisted and CPU usage stayed around 30% of 1
core capacity.
Libusb version was also considered, but version 1.0.20-2 which comes with
Ubuntu 16.04 seems quite up to date to be a problem (and is also the same
version deployed in the laptop).
I also checked dmesg output for errors, but everything seems fine.
We are also considering if the problem might be related to slower operations
over the hard disk (since ODROID works on a microSD card), ODROID USB bandwidth
capacity might being shared between both USB 3.0 ports (and therefore not
enough to handle both USRPs at the same time), or even if this is an Ubuntu
minimal problem. All of these seem pretty far shoots, and I have run out of
ideas.
Any additional information on the causes of ERROR_CODE_BAD_PACKET on rx6? Any
hint about how to solve this problem?
Best regards
[cid:[email protected]]
Román Rodríguez Pérez
Project Manager / GNSS Software Engineer
GMV
Isaac Newton, 11
P.T.M. Tres Cantos
E-28760 Madrid
Tel. +34 91 807 21 00
Fax +34 91 807 21 99
www.gmv.com <http://www.gmv.com/>
[cid:[email protected]]<http://www.facebook.com/infoGMV>
[cid:[email protected]]<http://www.twitter.com/infoGMV_es>
[cid:[email protected]]<https://plus.google.com/+Gmvcompany>
[cid:[email protected]]<http://www.youtube.com/infoGMV>
[cid:[email protected]]<https://www.linkedin.com/company/gmv>
[cid:[email protected]]<http://www.gmv.com/en/RSS>
[cid:[email protected]]<http://www.gmv.com/blog_gmv/language/en/>
P Please consider the environment before printing this e-mail.
______________________
This message including any attachments may contain confidential
information, according to our Information Security Management System,
and intended solely for a specific individual to whom they are addressed.
Any unauthorised copy, disclosure or distribution of this message
is strictly forbidden. If you have received this transmission in error,
please notify the sender immediately and delete it.
______________________
Este mensaje, y en su caso, cualquier fichero anexo al mismo,
puede contener informacion clasificada por su emisor como confidencial
en el marco de su Sistema de Gestion de Seguridad de la
Informacion siendo para uso exclusivo del destinatario, quedando
prohibida su divulgacion copia o distribucion a terceros sin la
autorizacion expresa del remitente. Si Vd. ha recibido este mensaje
erroneamente, se ruega lo notifique al remitente y proceda a su borrado.
Gracias por su colaboracion.
______________________
_______________________________________________
USRP-users mailing list
[email protected]
http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
