Dual monitor problem with kernel 5.3.6 and above

I haven’t been able to get dual monitors to work since upgrading to the 5.3.6 kernel. The problem happens with both F30 and F31, and upgrading to 5.3.7 hasn’t helped. My set up is an HP ProDesk with one monitor connected by VGA and the other connected with a VGA/USB converter. Previously, it has been working since about F25.

If I reboot with either monitor on the VGA/USB port and the other monitor disconnected, it works. But if I reboot with either monitor on the VGA port and the other monitor disconnected, it flashes black and white. If I reboot with both monitors connected at the same time, one monitor flashes black and white and the other stays black. Finally, if I reboot with one monitor on the VGA/USB port and then connect the second monitor while the first one is already up, nothing shows up on the second monitor and GNOME’s Display Settings do not reveal any dual monitor options.

Thanks for any advice.