#1602 flickering connecting to qemu vm

[tim]

version of qemu is 6.2.0 and vm is run using
qemu-system-x86_64 -cpu qemu64 -smp 4 -m 8G -drive file=/data/images/slack15.0_64bit_base.qcow2,format=qcow2 -cdrom /mnt/smb1/slackware/iso/slackware15.0-dvd_64bit.iso -boot c -net nic,macaddr=02:00:00:11:11:15,model=vmxnet3 -net bridge,br=br0 -enable-kvm -k en-gb -display vnc=:1 -monitor telnet:localhost:7100,server,nowait,nodelay

when connecting from a windows10 22h2 running updated tightvnc 2.8.75 to the vm, the screen constantly flickers, whether using fb console or xwindows on the qemu vm. it flickers with one session or more than one session. Connecting from windows to windows pc's gives no flicker.
using the previous version of tightvnc gives no flicker.
attached is a level9 log file of the flicker connection.

[tim]

(same problem with a qemu 7.2.0 vm)

[Anton]

could you test this viewer?

[tim]

that seems to fix the problem. no more flickering on remoting to qemu vm from windows client. thanks.

[tim]

i tested with single and double connection to qemu vm, both ok, and also two connections, one to qemu client, and one to windows client, again both ok .

[faginbagin]

Just wanted to add a "Me Too". First that 2.8.75 caused flickering from Windows 11 to Lubuntu desktop 22.04 running x11vnc both with and without a putty tunnel in-between (no VM) and that tightvnc-2.8.76-gpl-setup-64bit.msi fixed it, One Lubuntu machine has Intel UHD Graphics 630. The other has AMD/ATI Radeon HD 4200. I had also noticed the flickering on another Lubuntu machine with an old nVidia GT220 and the nouveau driver a few days ago but haven't tested with the bug fix. I assume it will work.