Re: KVM & mouse wheel [was PATCH]

[Marko Macek <Marko.Macek@gmx.net>]

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