hw_compat_rhel_8_0 contains { "virtio-gpu-pci", "edid", "false" }, This turns 'edid' off only for virtio-gpu-pci, but not for virtio-gpu-ccw. 'edid' needs to be turned off for virtio-gpu-ccw as well.
Clarification: 1. edid has been enabled (for all archs), so cd /sys/devices/[css0|pciXXX]/, cat $(find . -name 'edid') should return value (s. sample data below). 2. However, this bz's change assures that when migrating from a later machine model (e.g. s390-virtio-rhel8.2.0) the compatibility check must require edid=false. Sample output for edid on guest: # cat $(find . -name "edid") ������I4*�(xTL�&PT����% fA03@�.�2}�x �QEMU Monitor � J�$) E}e`Y�
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHBA-2020:3172