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Re: How to enter ddb on recent NetBSD/amd64 current

On Fri, Jul 17, 2015 at 06:04:57AM +0800, Paul Goyette wrote:

> My system reports:
> #  grep console /var/run/dmesg.boot
> wsdisplay0 at intelfb0 kbdmux 1: console (default, vt100 emulation)
> wskbd0 at ukbd0: console keyboard, using wsdisplay0
> ^^^^^^^^^^^^^^^^

this says:

- the early console code didn't detect a pckbd keyboard and
  then tested uskbd which later makes the wskbd attachment
  say "console keyboard".
- pckbd0 was not attached (it would get the first wskbd unit).
- ukbd0 was attached

> pckbc0          at isa?                 # pc keyboard controller
> pckbd*          at pckbc?               # PC keyboard

> # grep pckb /var/run/dmesg.boot
> pckbc0 at isa0 port 0x60-0x64

That's just pckbc, not pckbd.

PCKBD_CNATTACH_MAY_FAIL is the interesting option. It prevents pckbd
from being used as a console when no keyboard is found. It's the
default for i386 and amd64.

In Patrick's case we have:

>> wsdisplay0 at vga0 kbdmux 1: console (80x25, vt100 emulation)
>> wskbd0 at pckbd0: console keyboard, using wsdisplay0

- the early console code detected a pckbd keyboard.
- pckbd0 is attached

But he also sees "pckbdprobe: reset error", which means that the
pckbd driver attached but actually failed to see a keyboard.

I guess this is some kind of legacy emulation, where the USB keyboard
is presented as PS/2 hardware, but which is turned off as soon as
something is actually accessing the USB port.
This lets the console probe succeed, and the driver probe fail.

Maybe this emulation can be turned off in the BIOS. Otherwise,
it's probably necessary to just remove the pckbd driver from
the kernel config.

                                Michael van Elst
                                "A potential Snark may lurk in every tree."

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