[Qemu-devel] [Question]Ctrl_R or Alt_R Key Can Not Be Released through noVNC connection

[Xulei (Stone)]

Is there anyone can give me some information? I would be very grateful.

I have met several times that the right ctrl key or right alt key is in a 
pressed status and 
never released until I inject a sendkey qmp command.
I use noVNC, a web-based vnc, as my vnc client. What confused me is that, noVNC 
client
seems automatically convert the right ctrl/alt to the left ctrl/alt which means 
noVNC will
not be possible to send right ctrl/alt key to Qemu vnc sever. What's more, I 
have never 
pressed any ctrl or alt key. This may happen even as soon as I use vnc to 
connect my VM
which is now in the login interface. So I'm not sure it is a Qemu bug or noVNC 
bug.

The phenomenon is described as below:
1. When I press 'a', the vnc client outputs '^A', and 'b' is '^B'... Then I try
virsh qemu-monitor-command --hmp VM1 sendkey 0x9d    ---> 0x9d is left ctrl up 
scancode
it does not work.
but if I try
virsh qemu-monitor-command --hmp VM1 sendkey 0xe0-0x9d  ---->0xe0-0x9d is 
Ctrl_R up scancode
keyboard works right!
So I'm sure this phenomenon is caused because right ctrl key is in a pressed 
status.

2. Other several times, when I press '1', vnc outputs noting, '2' is '@', '7' 
is '{', '8' is '['...
It is obviously that my third function key (right alt/altgr) is in pressed. 
Then I try
virsh qemu-monitor-command --hmp VM1 sendkey 0xe0-0xb8  ---->0xe0-0xb8 is Alt_R 
up scancode
keyboard works again. The keymap of vnc, qemu and guestOS are all en-us.

Does qemu, in some cases, cannot right handle Ctrl_R or Ctrl_R key? Any patches 
can fix this?
Or, it is definitely a bug of noVNC?

noVNC version: 0.4
qemu version: 2.3