Bug#302729: kernel-image-2.6.8-2-386: PS/2 mouse support broken with KVM switch
Package: kernel-image-2.6.8-2-386
Version: 2.6.8-15
Severity: important
For all kernels more recent than 2.6.6-2-386, one of my machines (quite
an old ALi M1541-based one) treats all mouse movement as random noise
when my Intellimouse Explorer 3.0 is connected to my machine through my
I/O Gear CS-182 "MiniView Plus" KVM (keyboard/video/mouse) switch - any
mouse motion produces pointer motion all over the screen (both under
gpm/curses and X) and all kinds of button clicks - selects, pastes, etc.
Completely unusable. The problem is not present if I connect the mouse
directly to the computer, nor did it ever manifest under kernel 2.4. It
also doesn't seem to be an issue for the other machine on the switch,
which is a more recent nForce2-based box running kernel 2.6.9-2-k7.
This problem has been reported extensively elsewhere on kernel.org and
in discussion fora for other distributions, so feel free to ignore - my
main reason for writing is that after some experimentation (since I now
need a more bleeding-edge kernel than 2.6.6) I seem to have a fairly
trivial hack to work around the problem and since I've not seen it
documented elsewhere I thought it'd be worth writing down.
Firstly, although I've not seen this written down anywhere, it seems to
me that the problem actually seems to come in two forms: the first form
is where people encounter problems (loss of synchronisation, chaotic
pointer movement etc.) whenever they switch using the KVM; the second
form is a complete failure to initialise - i.e. the mouse/pointer seems
to be messed up from the moment the machine boots. My workaround is for
the second form - problems from boot time - and consists of repeatedly
reloading psmouse with increasing levels of protocol support before
starting the display manager - most easily accomplished by creating
something like /etc/rc2.d/S14psmouse-restart (for example) as follows:
#!/bin/sh
rmmod psmouse
modprobe psmouse proto=imps
rmmod psmouse
modprobe psmouse proto=exps
Missing either stage of this incremental approach to loading psmouse
will leave me with the original problem (so suggestions along the lines
of adding kernel boot parameters "psmouse.proto=bare" don't work for
me). I don't pretend to understand what's going on, I'll just say that
this works for me and hope that it might provide some insight into
what's happening for someone who does understand, and in the meantime
possibly help others get the full feature set from their mouse...
Conrad
-- System Information:
Debian Release: 3.1
APT prefers unstable
APT policy: (900, 'unstable')
Architecture: i386 (i586)
Kernel: Linux 2.6.8-2-386
Locale: LANG=en_GB, LC_CTYPE=en_GB (charmap=ISO-8859-1)
Versions of packages kernel-image-2.6.8-2-386 depends on:
ii coreutils [fileutils] 5.2.1-2 The GNU core utilities
ii fileutils 5.2.1-2 The GNU file management utilities
ii initrd-tools 0.1.77 tools to create initrd image for p
ii module-init-tools 3.2-pre1-2 tools for managing Linux kernel mo
-- no debconf information
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