Re: serio / atkbd / PS/2 Strangeness with Serial port adapter

From: Dmitry Torokhov
Date: Mon Aug 24 2009 - 20:22:29 EST


On Monday 24 August 2009 17:09:20 Matt Causey wrote:
> On Mon, Aug 10, 2009 at 1:34 AM, Dmitry
> Torokhov<dmitry.torokhov@xxxxxxxxx> wrote:
>
> >> [ 459.004227] drivers/input/serio/i8042.c: fe <- i8042 (interrupt, 1,
> >> 12, timeout) [445118]
> >> [20171.684870] drivers/input/serio/i8042.c: 0b <- i8042 (interrupt, 0,
> >> 1) [20162195]
> >>
> >> However - the atkbd driver does not pick the device up at all.
> >>
> >
> > Your device is steadely refusing to say that it is a keyboard - and so
> > atkbd driver does not bind to it.
> >
> >> So, I did find a workaround (which is NOT acceptable for this
> >> deployment). Remember the PS/2 'wedge' I mentioned? Well, it has an
> >> extra PS/2 port for your keyboard. If I connect a PS/2 keyboard to
> >> that thing, suddenly my scanner starts working.
> >>
> >> We see some chatter from the controller driver, then one of these:
> >>
> >> [23811.805578] input: AT Translated Set 2 keyboard as
> >> /devices/platform/i8042/serio0/input/input6
> >>
> >
> > That happened because apparently the 'wedge' passes the inquirys to
> > the real keyboard and it answers propery.
> >
> > I think the "i8042.dumbkbd" kernel parameter will solve your issue.
> >
> > --
> > Dmitry
> >
>
> That's great. I think it's the only option that I did not try. ;-)
> Works great!
>
> In case it matters:
>
> blah blah/ # dmesg | grep i8042
> [ 0.000000] Kernel command line: initrd=ramdisk.gz
> video="vesafb:mtrr,ywrap,1024x768-32@85" i8042.dumbkbd
> BOOT_IMAGE=bzImage auto
> [ 14.046511] serio: i8042 KBD port at 0x60,0x64 irq 1
> [ 14.046578] serio: i8042 AUX port at 0x60,0x64 irq 12
> [ 15.804210] input: AT Translated Set 2 keyboard as
> /devices/platform/i8042/serio0/input/input2
> blah blah/ #
>
> Looks like it just decides that there must be a keyboard there,
> whether or not there really is one.
>
> Are there any downsides to using this kernel parameter?
>

The kernel will not control LEDs on the keyboard nor will it be able
to control hardware autorepeat parameters (software autorepeat should
still work fine).

--
Dmitry
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