Comment # 4 on bug 1171455 from Fabian Vogt

(In reply to Liang Yan from comment #2)
> It seems EDID support for virtio-vgpu has been merged since QEMU-4.0,
> however it is turned off by default.
> 
> @Ludwing Could you try again with "edid=on" from qemu command line. Also
> since 15.2 is about to expire, could you try on 15.3, thanks.

IIRC I tested this with QEMU 4.x and the missing part was in seabios, see
comment 1. Was that implemented differently?