I installed gr-soapy for 3.8 (using PyBOMBS), plugged in a RSP1A, and it worked. This is the LibreSpace code, as we don't have in-tree Soapy support in 3.8.
I'd already installed the soapy libs (v0.8.1-g1cf5a539) and driver modules, also via PyBOMBS. Make sure it's not a soapy or usb problem by running
SoapySDRUtil --probe
My test was just a Soapy Source connected to a QT GUI Sink. Sample rate is 1M, and so is the bandwidth in the Soapy Source on the RF tab. Don't know if that matters. Everything else is defaults.