Mirics MSi2500 support on Linux

[Phil B]

Hello all,

I've been a user of GQRX for several years with a generic rtl-sdr dongle and been pretty happy with it so I recently picked up one of the MSi.SDR dongles hoping to improve functionality and performance.  I believe the dongle I have is functionally equivalent to the SDRPlay RSP1 (not the 1a) with the addition of a TCXO.  The information on actually using these devices on Linux is a bit thin so I'm hoping someone can point me in the right direction re: driver support and configuration.

After blacklisting the kernel driver, I've managed to verify basic functionality with GQRX and the userspace driver but have run into a number of issues.  Specifically I am having problems with:

1) Dead zones in the spectrum (<~48MHz, ~300-485MHz)

2) Can't set the frequency >~1678MHz (supposedly the Mirics can go up to 2GHz)

3) Gain control (AGC and manual) appears non-functional

4) I seem to have to choose between my dongles (i.e. I can get the MSi *or* the rtl-sdr working if they are the only one plugged in, but not when both are plugged in at the same time)

This is using the default GQRX 2.11.5 install for Debian 10.  So I'm wondering how much of what I'm running into falls into the category of driver/configuration issues vs. 'yeah, that sounds about right' vs. the GQRX build for Debian?

Thanks,

Phil