bin/79376: moused causes random mouse events with a PS/2 mouse on FreeBSD-4.11

Jukka Ukkonen jau at
Wed Mar 30 09:20:04 PST 2005

>Number:         79376
>Category:       bin
>Synopsis:       moused causes random mouse events with a PS/2 mouse on FreeBSD-4.11
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    freebsd-bugs
>State:          open
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Wed Mar 30 17:20:03 GMT 2005
>Originator:     Jukka Ukkonen
>Release:        FreeBSD 4.11-STABLE
FreeBSD mjolnir 4.11-STABLE FreeBSD 4.11-STABLE #3: Tue Mar 29 12:08:01 EEST 2005     root at mjolnir:/usr/obj/home/src/sys/Mjolnir  i386

Additionally there are:
- XFree86-libraries-4.4.0_3 and
- XFree86-Server-4.4.0_7.

      When using moused to handle a PS/2 mouse there are a lot of random
mouse events in X11 applications. It is quite typical to see key press and
drag marking something while one is really only moving the mouse to completely
different direction, etc.
This problem is not visible at all when the XFree86 server handles reads
/dev/psm0 itself.
The problem only appears when moused is used to handle /dev/psm0 and pass
the events to /dev/sysmouse.

Without having any deeper understanding about how moused works, I can only
guess what is going on, but I try describe the symptoms I have seen.
It seems like either moused somehow drops out of sync with the mouse data
stream or it fails somehow trying to combine incoming mouse events to larger
events to before passing them to /dev/sysmouse (or something similar).
Anyhow on occasion (actually all too often) moused seems to trigger these
totally erratic bursts of mouse events.
The events really come in bursts and usually they cause a lot of harm and
confusion, because one cannot really know any more what commands might
have been entered to and xterm with a shell, what new files have been
created, what might have been deleted, etc.
The erratic events simply copy and paste random strings or often times
several lines from the screen. Often the copied text might end up in
another xterm window then where the text came from, etc.

The fact that I no similar problems when using the same mouse device
on its own with XFree86 has convinced me that neither the device itself,
nor the psm driver, nor XFree86 is the culprit.
So, this practically leaves only moused left to blame.

      Take 4.11-STABLE with a PS/2 intellimouse with roller, moused with options
"-p /dev/psm0 -t auto", and make XFree86-Server-4.4.0_7 read its mouse events
from /dev/sysmouse.
For me this patently repeats the problem within a few minutes.
A quicker means to make the problem appear would probably be pressing the left
mouse button and moving the mouse quickly back and forth a few times.

      I really wish I knew. I'd be posting the fix instead of trying to describe
the symptoms now, if I had any clue. ;-)


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