Why does the KVM virtual machine console freeze in full screen mode?

Question

linux

The situation is incomprehensible.
QEMU 2.8.1-r2, libvirt 3.1.0, virt-manager 1.4.0-r3. Calculate Linux 17 bucket 4.4.39 (tried 4.9.17 - no difference).
Virtual machine with Win7, SPICE display, QXL video. Until some time (about a month ago) everything worked without any problems - since its creation two years ago. But some unknown problems have recently begun, which are expressed in the fact that the image on the console screen in virt-manager "freezes". That is, you open the console - it shows the Windows splash screen. You log in and go to full screen mode - the image "freezes" and does not update, when you return to the window - stripes, artifacts, you have to close the console and open it again - after opening again you see the image as it should be (that is, the actions were performed, but they didn't show up on the screen. Moreover, this garbage occurs only if the resolution of the console is equal to the physical resolution of the monitor (in this case, 1920x1200),
The question is what to do and who is to blame? :) Is there a problem in the bucket, in qemu, in firewood on QXL? Firewood was updated from the spice-space site, a couple of VirtIO Serial type devices were found (what the hell are they to me?). The bucket is loaded without nomodeset - for some reason, lately, loading with nomodeset again causes a hang after the inscription "Loading initial ramdisk".

Answer 1

I will answer myself.
QEMU 2.9.0-r2, libvirt 3.2.0, virt-manager 1.4.1, spice 0.13.3-r1, spice-gtk 0.33-r2, bucket 4.9.17
It's not clear what fixed the console from this. It's just that after another rebuild, I didn't see the usual "freezing" of virt-manager icons in full screen mode - and OMG - everything was fixed. Now everything works as it should. Bucket loaded without nomodeset - calculate=video:intel splash=off
I don't know for how long...