As reported in the Ubuntu thread, gqrx is useless with SDRplay. There is no way to change the gain, the sample rate drop down menu is vacant, typed in values aren't saved, and reception is only possible if the signal is at zero offset, which means the DC carrier causes interference. There are also a huge number of spurious signals and the noise floor jumps around. I'm using the Arch package with gnuradio version 3.7.7 but with gr-osmosdr and gqrx installed from the latest (as of today) git version instead of the binary packages. This was not good news as I spend most of my computer time in Linux.
The good news is the sdr-j FM and SW receivers work fine (http://www.sdr-j.tk/index.html). Compiling them is a little tricky, but the manuals explain it well and it will work on Arch Linux. I do a fair amount of compiling from source on this machine so other than the SDRplay API I didn't have to install any additional software.
I haven't had a chance to test it with a receiver I built using gnuradio-companion but hope to soon. I'll report back if the source works any better than gqrx. If you're having trouble running SDRplay under Linux, I'll try to help if you post the question here. Most of my experience is with Arch but as noted I do have Ubuntu on a virtual machine for testing.
Reason: No reason