Re: KVM & mouse wheel [was PATCH]

[Marko Macek]

Dmitry Torokhov wrote:

> Hi,
>
> On Tuesday 03 August 2004 10:26 am, Marko Macek wrote:
>  
>
> > Hello!
> >
> > A few months ago I posted about problems with 2.6 kernel, KVM and mouse
> > wheel.
> >
> > I was using 2.4 kernel until recently, but with the switch to FC2 with
> > 2.6 kernel this problem became much more annoying.
> >
> > My mouse is Logitech MX 510.
> >
> > I figured out a few things.
> >
> > 1. Trying to set the mouse/kvm into a stream mode makes things insane.
> > Since streaming mode is supposed to be the default, I propose not
> > doing this at all. I haven't researched this further.
> >
> > -      psmouse_command(psmouse, param, PSMOUSE_CMD_SETSTREAM);
> >    
>
> Could you describe what insane mean? If you take the KVM out of the picture
> is the mouse still instane?
>  
Insane means that the mouse is moving really slowly, jumping around and 
buttons
work erratically. I did some more experiments and it seems that if I put 
this command
before the resolution/rate/scaling setting it seems to do no harm (the 
mouse works perfectly).
I'd still prefer to remove it since I see no need for it.

> > 2. synaptics_detect hoses imps and exps detection. Resetting the mouse
> > after failed detect fixes it. This makes 'imps' and 'exps' protocols
> > work when used as proto=imps or proto=exps. Wheel works, I haven't tried
> > the buttons.
> >
> >    
>
> Again, does it work without the KVM?
>  
Yes, without the KVM the mouse works perfectly.

>  
>
> > 3. PS2++ detection correctly detects Logitech MX mouse but doesn't
> > enable the PS2PP protocol, because of unexpected results in this code:
> >
> > 	param[0] = param[1] = param[2] = 0;
> >         ps2pp_cmd(psmouse, param, 0x39); /* Magic knock */
> >         ps2pp_cmd(psmouse, param, 0xDB);
> >
> >         if ((param[0] & 0x78) == 0x48 &&
> >             (param[1] & 0xf3) == 0xc2 &&
> >             (param[2] & 0x03) == ((param[1] >> 2) & 3)) {
> >                 ps2pp_set_smartscroll(psmouse);
> > 	        protocol = PSMOUSE_PS2PP;
> >         }
> >
> > The returned param array in my case is: 08 01 00 or 08 00 00 (hex)
> > (without KVM: C8 C2 64)
> >
> > I don't understand what this code is trying to check or why the protocol
> > is only set conditionally. If I set it unconditionally (swap last 2
> > lines) the PS2++ protocol now works including detection of all buttons
> > (I don't really need the buttons, just the wheel).
> >
> >    
>
> Apparently your KVM doctors the data stream from the mouse. The driver
> tries to play safe and only switches to PS2++ protocol if mouse responds
> properly, otherwise there is a chance that it uses PS2++ with mouse that
> does not actually support it. 
>
>  
Yeah, that's why I decided to fallback to im/exps modes instead.

I have now also successfuly used the extra mouse buttons with 'exps' 
protocol.
So only the 'task' button is not supported with my previous patch (because
it requires PS2++ mode).

> > This is not included in the patch. The alternative solution
> > is to reset the mouse again and resume probing for imps or exps.
> >
> >    
>
> It will be probed for imps/exps if PS2++ fails. Now I suspect that your
> particular KVM does not expect any extended probes and gets confused by
> them.
>  
I have also seen comments in X sources about needing to reset the mouse 
after
each unsuccessful probe for best compatibility.

Mark

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