No keyboard after ports update, 2x moused_enable="YES" culprit

perryh at perryh at
Mon May 16 03:15:29 UTC 2011

Polytropon <freebsd at> wrote:

> Do _NOT_ hotplug the PS/2 port! It's not capable of that!
> I've seen myself in the past that trying so caused a mainboard
> to fly into the garbage can - as hotplugging the keyboard
> seemed to have damaged the PS/2 port (it didn't work anymore,
> with no keyboard).

This is conventional wisdom, and I believed it until I came across,
as an enclosure with a Belkin "F8E206c" PS/2 keyboard that had 3
extra keys*, specific instructions to unplug the keyboard, wait 5
seconds, and replug it to get past a BIOS incompatibility on some
Intel boards using the SE440BX-2 chipset.  (The next step was to
upgrade the BIOS, but the hotplug exercise was necessary to get
to the point of being _able_ to upgrade the BIOS.)

* Power, Sleep, & WakeUp; presumably intended for ACPI or APM.

> However, you actually CAN do this with USB.

Yes, USB was designed to be hot-pluggable.

> And I've done hotplugging with an old AT ("big" 5 pin keyboard
> connector) and HIL connect/disconnect at the keyboard (!) without
> any problem (IBM model M, the famous one).

The AT and PS/2 keyboard interfaces are electrically identical --
only the physical connector is different.  (I have seen, and used,
adapters to connect either type of keyboard to the other type of
system.  Such adapters have no active components, just the two
connectors wired together.)

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