After I switch an HDMI source from 1080p60 to 1080p50 hundreds of times, the VIC code is read as 0.
What causes this problem?
This is a known issue in the Vivado 2018.3 and 2019.1 HDMI Receiver Subsystem only.
Occasionally an incoming stream causes phase change in-between channels.
Re-alignment needs to be applied to fix this problem.
This issue will be fixed in Vivado 2019.2 and later versions.