devd started with single-user mode?

David Demelier demelier.david at
Mon Mar 21 11:15:38 UTC 2011

On 21/03/2011 12:11, Polytropon wrote:
> On Mon, 21 Mar 2011 11:45:06 +0100, David Demelier<demelier.david at>  wrote:
>> By the way why is kbdmux needed for an usb keyboard? Should not be
>> managed by ukbd only?
>> I don't understand .. But thanks for the patch.
> Basically, the kbdmux option "wires keyboards in parallel", so
> you can use both keyboards (assume they are physically present)
> at the same time, like "one keyboard for each hand". If this
> option was not present, you would have to use "kbdcontrol -k"
> to switch from one keyboard (the currently active one) to the
> other (not usable). Problems may occur if your mainboard does
> provide an AT style keyboard (usually with PS/2 connector) as
> atkbdc0 and adkbd0 (controller and keyboard) even if there is
> no physical keyboard attached. This would then usually become
> the primary keyboard. A USB keyboard, detected later on as
> ukbd0, would not automatically be activated (or switched over
> to by a "kbdcontrol -k" command issued by devd) and can therefore
> not be used, even if physically present (in opposite to the
> "phantom" keyboard atkbd0). The kbdmux option makes _all_
> keyboards available for input (without using "kbdcontrol -k"
> and without dependency of devd) so the USB keyboard will be
> used, the AT "phantom" keyboard will be ignored (which is good
> when it's not even present).
> So basically, kbdmux means "use all of them", while its absence
> means "use this or that".

Thanks for this information :-) I understood. I hope the patch proposed 
will be MFC to -STABLE then.

Kind regards,

David Demelier

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