PlutoSDR issues in 2.7

[Jason Pontious]

I wanted to post my findings with the PlutoSDR and GQRX 2.7.  I've spent a bit of time getting it to work so hopefully this will help some others.

All of the following is using the MyriadRF PPA's with Ubuntu 17.04.

I was initially given the following error.

FATAL: No Pluto device found

This was solved by grabbing the gr-osmocom-gqrx from github and compiling the plutosdr branch manually.  Is the hardcoded URI that was added in the most recent commit in the version that is on the Ubuntu PPA's?  My guess is that the last commit is missing from what is compiled in the ppa repo's.

2nd issue is that an IP uri is my only option (e.g., ip:192.168.2.1).  Usb should be an option as that works on the Windows side and produces better results for me.  I can use 4MSPS with no drops where with IP I can only us 3MSPS. Using "iio_info -s" reported the following.

Library version: 0.10 (git tag: v0.10)

Compiled with backends: local xml ip

No contexts found.

Notice how usb is missing from the compiled backends.  I was able to download the libiio source from github and compile my own to fix this also.  It requires libusb1.0-dev installed first and it automatically compiles the usb backend into the lib.  This is also why the auto finding feature is not working and requires a hard coded uri for gqrx right now.  Once I recompiled I got this ....

Library version: 0.10 (git tag: 82a23b2)

Compiled with backends: local xml ip usb

Available contexts:

0: 0456:b673 (Analog Devices Inc. PlutoSDR (ADALM-PLUTO)), serial=xxxxxxxxxx [usb:x.x.x]

Hopefully this information is of use and can be fixed in the ppa repo's in the future.

Thanks for all the hard work that goes into this project!

[Alexandru Csete]

Hello Jason,

Thanks for the feedback. It all happened under lot of time pressure as
I had other things planned for the weekend. So it is very likely that
mistakes happened :)

I am, however, pretty sure the all commits from the plutosdr branch
are in the PPA and I have also tested PlutoSDR input with the PPA
packages. Since iio_info does not find the network device, it seems
your system is not configured for USB networking, which is a bit
strange.

Anyway, I will include usb support to libiio; however, it will also
require updating gr-osmosdr to accept uri=... in the device string.

Alex

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[Alexandru Csete]

You were right, Jason. I forgot to rebuild the package for Ubutnu
17.04 using the latest patch. 14.04 and 16.04 were OK, which is why I
didn't notice.

Anyway, I have now rebuild libiio to include USB support and there is
also an updated gr-osmosdr package with the latest patch. Please try
and see if they work now for you, but make sure you uninstall the
source builds first.

Alex

[Jason Pontious]

Thanks. I'll take a look later. I have no doubt you fixed it. It appeared like a minor issue. I appreciate all the time and effort you put in on this project.

I have plans to put in the uri into the args as I want to test out a USB gigabit adapter to see how that affects performance. If you are not opposed I'll submit a pull request once I've tested it.

[Alexandru Csete]

On Sat, Aug 26, 2017 at 2:51 PM, Jason Pontious <jpon...@gmail.com> wrote:
>
> I have plans to put in the uri into the args as I want to test out a USB gigabit
> adapter to see how that affects performance. If you are not opposed I'll submit
> a pull request once I've tested it.
>

Already done:
https://github.com/csete/gr-osmosdr-gqrx/commit/823b9c22e58b02519db2a2c9ed6d4ff476c24b26

Just need to package it :D

I would be very interested to know if one can use wildcard or some
auto detection when using USB.

Alex

[Jason Pontious]

That's even better when the work I was planning on doing is already done.  

Everything is working now.  Including the uri in the latest commit.  The USB Gigabit network adapter didn't improve anything.  I'm not getting any better performance from it.  Might look into tweaking the buffers.

So I've looked a bit into USB auto detection.  I can not find a wild card pattern for it.  I've looked through the code and there is a scan feature that is automatically used when you pass in a blank uri into the pluto source.

See pluto_source_impl::get_uri

This appears to scan the for devices on the usb interface and use the first one found.  As another interesting note.  ip:pluto.local found the device even when it was connected with the USB Gigabit adapter and not connected directly via USB.

Hope this helps. 

 

[Alexandru Csete]

for the buffer, please see this thread:
https://github.com/csete/gr-osmosdr-gqrx/pull/3

I need to work on other projects for a while and will not be able to
play much with plutosdr integration. That's why I tried to push out
these updates in a hurry.

Alex

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