Hi folks,

I have a weird issue I've been attempting to troubleshoot for a bit and I'm
stuck.

So setup:
USRP B205 connected to a Raspberry Pi 3 (so USB 2 mode)
Huawei E3372 USB LTE adapter connected as well
Running the latest Raspbian (stretch)

Problem:
I'm using C++ code to read stream blocks from the device (800,000 samples
with the USRP set to 8 MSPS, so basically 1 ms of data).  Without the LTE
it works fine, I get only infrequent overruns and the rest of the logic
works fine.  As soon as the LTE is plugged in and the corresponding
ethernet interface is up, the recv call can't get a whole block of data
(recv returns 0 bytes).  If I ifconfig down the interface or unplug the LTE
it goes back to working just fine. Plug it back in or ifconfig up the
interface, problem returns.  Of note, there is another network connection
up on the wifi so the LTE is getting a lower priority in the routing table
and there isn't any data going across it (I confirmed it with the
statistics in ifconfig for that interface).

So troubleshooting so far:
I'm running the latest UHD code (3.11.1 - Just git pulled the latest today
and rebuilt it).
Works fine on Ubuntu 16.04.  No issues with both connected (so it's not my
code :))
There doesn't appear to be any firmware updates to apply to the Huawei
(always worth a shot)
The huawei_cdc_ncm linux driver doesn't appear to have had any updates in
the past couple years (so doesn't look like a linux driver update)
Nothing showing up from dmesg or in /var/log/syslog or /var/log/messages
related to failed recv's.
Made sure there wasn't any data going over the LTE to rule out it's doing
large data transfers
I tested with other USB devices in place of the LTE.  Works fine.  So not
the port or a general USB issue.
I tried opening the device with num_recv_frames=1024 to see if that would
help, no luck.
I also tried increasing the timeout from the default 0.1 to 0.2 on the recv
call with no luck there either.

Any suggestions?
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