Re: [Qemu-devel] [PATCH v2] ui/input: fix event emitting of repeated combined keys

[Gerd Hoffmann <kraxel@redhat.com>]

On Fr, 2014-09-26 at 18:53 +0800, Amos Kong wrote:
> On Fri, Sep 26, 2014 at 12:36:50PM +0200, Gerd Hoffmann wrote:
> > On Fr, 2014-09-26 at 18:23 +0800, Amos Kong wrote:
> > > Currently we emit press events of combined keys first, then emit
> > > release events by reverse order. But it doesn't match with physical
> > > keyboard if the keys contain continued & repeated keys.
> > > 
> > > For example, (qemu) sendkey a-b-b
> > 
> > Hmm, somehow I don't feel like building too much magic into this.
> > If you want send Ctrl-somekey twice just use two sendkey commands ...
> 
> 
> Before this patch, If 'sendkey r-o-o-t', only 'rot' can be inputted.

To type 'root' you should use

sendkey r
sendkey o
sendkey o
sendkey t

Multiple keys in sendkey is meant for multiple keys pressed at the same
time, i.e. ctrl-alt-del, not for sending key sequences and typing words.

> People want to panic windows by sending Ctrl-Scrool-Scrool
> http://msdn.microsoft.com/en-us/library/windows/hardware/ff545499(v=vs.85).aspx
> But current events order doesn't work.

sendkey Ctrl-Scroll
sendkey Ctrl-Scroll

> In physical keyboard. We can prese Ctrl first, then press & release
> Scroll twice, then release Ctrl. It's very common behavior.

In most cases it doesn't matter whenever you release the modifier key or
not.  The windows panic hotkey might be the exception from the rule
though.

> So this fix just reference the physical implement, if you want to
> input same key twice, you have to release it before second pressing.
> (here we ignore the auto-repeat feature)

sendkey doesn't cover that use case indeed.

/me wonders what happened to the input-send-event patch from marcelo,
see http://patchwork.ozlabs.org/patch/360649/

According to patchwork I've picked it up.  But it is neither upstream
nor in my local input branch.  And I can't remember what happened :(
Marcelo, any clue?  Maybe I should just re-queue it ...

The input-send-event gives you fine-grained control about the exact
input event sequence and it can handle your use case without problems.

cheers,
  Gerd