Re: [Qemu-devel] [PATCH] new SDL keyboard shortcuts to start and stop VM

[Anthony Liguori]

Kevin Wolf wrote:
> Am 20.10.2009 00:20, schrieb Anthony Liguori:
>   
> > Mulyadi Santosa wrote:
> >     
> > > IMO, it would be faster if we provide keyboard shortcuts that will
> > > stop and resume VM execution right from SDL guest interface, rather
> > > than switching to console monitor first and type "s" or "c"
> > > respectively.
> > >   
> > >       
> > Is this really common of an operation that you would need an escape key 
> > for it?
> >
> > Why are you so frequently stopping and continuing a guest?
> >     
>
> Why are you all trying to explain to him that actually he doesn't want
> to have this feature? I could have used it, too, at times (stop the
> guest to have enough time to attach gdb, for example). There are other
> ways to do it (although they are not as simple) and I used them, but
> that doesn't make this feature less useful.
>
> Does it take anything away for you? Or do you have plans to use those
> keys otherwise? If not, why not add a feature that some might find
> useful, even though others don't?
>   

There is such a thing as feature bloat.  It leads to very confusing 
behavior for users.  It also increases the testing matrix.

As it turns out, there's a better way to do what he's looking for that 
requires no changes.  Had we just taken this patch, then that's another 
feature that has to be tested for SDL whenever there's a change there.  
It also means there will be differing behavior for VNC so it probably 
needs to be supported there.  But then for something like libvirt, it's 
not going to expect that something else pauses/starts a VM.

Features are not free.  They have long term maintenance costs so we 
should consider whether a feature really offers value.

Regards,

Anthony Liguori