linux-kernel - Re: PATCH: PR Input Devives/2082: PS/2 mouse out of sync after switching with KVM switch

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Message-ID: <d120d5000710300953kd145c7fg53f4fa4d41fbc9c3@mail.gmail.com>
Date:	Tue, 30 Oct 2007 12:53:17 -0400
From:	"Dmitry Torokhov" <dmitry.torokhov@...il.com>
To:	"H.J. Lu" <hjl@...on.org>
Cc:	"linux kernel" <linux-kernel@...r.kernel.org>
Subject: Re: PATCH: PR Input Devives/2082: PS/2 mouse out of sync after switching with KVM switch

Hi,

On 10/30/07, H.J. Lu <hjl@...on.org> wrote:
> The bug report is at
>
> http://bugzilla.kernel.org/show_bug.cgi?id=2082
>
> Problem Description: When switching to another machine with a KVM
> switch and back, the mouse is out of control, with X.Org.  To recover,
>  I have to unplug the mouse cable and plug it back.
>
> Steps to reproduce: Have a wheel mouse connected and X.Org.  Keyboard,
> Mouse and Video are connected to a KVM switch. Switch to another
> machine and back.  You have lost the usage of wheel on mouse.
>
> This patch for 2.6.23 tries to reconnect the mouse after KVM switch.
> It doesn't completely solve the problem. Mouse still got a few random
> bytes after KVM switch.

Have you tried psmouse.resync_time=5 option?

Any change you coudl do

echo 1 > /sys/module/i8042/parameters/debug

before switrching KVM back and forth and send me dmesg?

> But it recovers with kernel message:
>
> psmouse.c: Wheel Mouse at isa0060/serio1/input0 lost synchronization, issuing reconnect request.
>
> instead of
>
> psmouse.c: Wheel Mouse at isa0060/serio1/input0 lost synchronization, throwing 3 bytes away.
>
> and never recovering from it.
>

I am hesitant queuing reconnect immediately - if the byte was delayed
because embedded controller was busy doing something else and we start
querying mouse at the wrong time we might lose mouse altogether.

-- 
Dmitry
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