Re: [Qemu-devel] Implementation of multi-touch in linux mobile operating system using QEMU.

[Alexander Graf]

On 10.09.2009, at 16:04, Amey Moghe wrote:

> Hello all,
>
> Just wanted to add something more to my previous mail I had posted  
> on mailing list. Actually I am studying the input flow from host OS  
> to qemu which is installed on plain linux distro like ubuntu 8.10  
> which I am using currently since my aim is to add multi touch  
> support so that the guest OS installed inside qemu can interpret  
> multi touch information from qemu. And for multi-touch information  
> on Host machine I am going to use MPX . So in this scenario I came  
> to know by my understanding that there may be two channels for qemu  
> to have inputs from host OS i.e.
>
> 1) SDL
> 2) VNC

3) Cocoa
4) Curses

> So,I am confused about which way qemu uses for having input events  
> from host OS. Is it SDL or VNC ? Also please if anybody can suggest  
> me some documentation regarding all the above matter which I can  
> refer to, it will be better for me.

It depends.

If you start qemu without options on Linux or Windows, you get the SDL  
in- and output (sdl.c)
Starting it with -vnc :0 starts a vnc server, giving the IO handling  
to vnc.c
If you use -curses, you'll get a curses backend. I don't know if that  
does support mouse, it's mostly about text mode.
And when you're on Mac OS X, you get a native Cocoa backend instead of  
the SDL one (cocoa.m).

So qemu has several backends built-in. IMHO having multi touch support  
would make sense to have in sdl.c first, with an architecture that  
could be easily extended to the other backends if someone needs it.

Does that clarify the situation?

Alex