dvbv5_scan and w_scan, tools for scanning for TV channels (in my case, US
ATSC), are able to lock tuning but not extract metadata using kernel
4.12.14-lp151.28.10-default on a Ryzen 2700X using a Hauppage HVR-950Q tuner
(which worked fine on 42.3 and possibly 15.0).  Packages I'm using for channel
scanning:

w_scan-20170107-lp151.2.3.x86_64
dvb-utils-1.14.1-lp151.2.5.x86_64
libdvbv5-0-1.14.1-lp151.2.5.x86_64

With kernel-default-5.2.1-2.1.gbf5c01b.x86_64, the scanning succeeds (hence I'm
filing this against the kernel).

w_scan emits the following error:

tune to: 8VSB     f=503000 kHz (0:0:0) (time: 02:52.484) 
 (0.692sec): SCL 
        Info: no data from PAT after 6 seconds
        Info: no data from VCT(terr) after 26 seconds
        Info: no data from VCT(cable) after 26 seconds

I'm able to watch TV (using dvbv5-zap) just fine; it's only the scanning that
fails.