+++ This bug was initially created as a clone of Bug #665017 +++
qemu doesn't enqueue mouse events, it just records the latest mouse state. This can cause some lost mouse double clicks if the events are not processed fast enough. In particular, dragging/doubleclicking are impossible on a high latency connection (e.g. Milan->Phoenix->Brno).
I'll post patches to upstream QEMU to fix this, based on these xen-unstable qemu.git patches:
Queue some mouse events.
Try to fix USB HID and make the HID reports readable
Fix new USB HID queueing
Reproduce the issue on kvm-83-224
Verified the issue on kvm-83-235
steps:( for this case I use the slowest vpn proxy address to test)
1.start win08 guest as followings :
eg:/usr/libexec/qemu-kvm -M rhel5.6.0 -m 2048 -smp 4,sockets=4,cores=1,threads=1 -name windows2008_qcow2 -uuid cddeab65-2ded-43db-094a-fd4f8ec2d69f -monitor stdio -localtime -no-kvm-pit-reinjection -boot c -drive file=/home/windows08.qcow2,if=ide,bus=0,unit=0,format=qcow2,cache=none -drive file=/home/en_windows_server_2008_datacenter_enterprise_standard_sp2_x64_dvd_342336.iso,if=ide,media=cdrom,bus=1,unit=0,readonly=on,format=raw -net nic,macaddr=54:52:00:4f:26:51,vlan=0 -net tap,vlan=0 -serial pty -parallel none -usb -usbdevice tablet -vnc :1 -k en-us -balloon none
2.in the guest ,modified the double-click speed to fastest in the control panel.
3,Tried to open some folder or files by using double-click
on kvm-83-224 ,50% times double clicks in the guest does *not* work.
on kvm-83-235 ,random times double clicks in the guest does *not* work
Based on above ,this issue has been fixed.
Technical note added. If any revisions are required, please edit the "Technical Notes" field
accordingly. All revisions will be proofread by the Engineering Content Services team.
The QEMU emulator did not enqueue mouse events; it simply records the latest mouse state. Prior to this update, double click or dragging mouse events were sometimes lost, especially on high-latency connections. Now, the code for mouse descriptors has been fixed, and lost mouse events occur much less frequently.
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.