https://bugs.winehq.org/show_bug.cgi?id=44709
--- Comment #1 from François Gouget fgouget@codeweavers.com --- Currently we take the screenshots through Libvirt and thus QEmu + Spice. However QEmu does not have access to the screen of VMs that use PCI-passthrough graphics cards. So for these we may need to take the screenshots from inside the guest.
Furthermore the screenshot is transferred uncompressed from the VM host to the TestBot server which are not on the same LAN. That's pretty inefficient and may limit how often we can take screenshots. There taking screenshots from within the guest could be an advantage as it could deduplicate identical screenshots before their transfer.
For instance the client tool could create a new png file every time the screen changed, and then the TestBot could retrieve the list of files and retrieve them with TestAgent.