[vbox-dev] UseMouse is skipping mouse clicks intermittently

[Vic Lee]

Hi!

I am not sure if anyone is aware of the issue, but for quite a while I 
notice that virtualbox is obviously skipping my mouse clicks. Depending 
on whether I have guest mouse driver installed or not, whether I connect 
to console or through RDP, the skip rate may be different but not solved.

I spent some time debugging from source and I am able to identify the 
issue is in function usbHidMousePutEventAbs() in UsbMouse.cpp. There is 
a call to usbHidQueueRemoveHead (line 801) which will return NULL 
whenever my click is skipped. The problem here is that if the button 
state is not being changed, it will be ok to skip mouse events; but if 
pThs->PtrDelta.btn != fButtonStates, the event should not be skipped, 
but must be queued until available. Otherwise either mouse press or 
release event will not be reported to the host and is quite annoying. 
usbHidMousePutEvent() function should be the same as well.

UsbKbd.cpp, however, is properly queuing pending key events, thus I 
never experience missed keys. Any idea to improve UsbMouse?

Thanks,

Vic