svn commit: r355936 - in head/sys: arm/broadcom/bcm2835 arm/freescale/imx arm/ti/am335x arm/versatile powerpc/ofw

[Kyle Evans]

On Fri, Dec 20, 2019 at 10:22 AM Kyle Evans <kevans at freebsd.org> wrote:
>
> Author: kevans
> Date: Fri Dec 20 16:22:14 2019
> New Revision: 355936
> URL: https://svnweb.freebsd.org/changeset/base/355936
>
> Log:
>   Kill off dummy kbd drivers
>
>   As far as I can tell, these are an artifact of times when linker sets
>   couldn't be empty, otherwise the kernel build would fail due to unresolved
>   symbols. hselasky fixed this in r268138, and I've audited the kbd portions
>   to make sure nothing would blow up due to the empty linker set and
>   successfully compiled+ran a kernel with no keyboard support at all.
>
>   Kill them off now since they're no longer required.
>
>   MFC after:    1 week
>

It turns out that I missed one of these in
^/sys/dev/terasic/mtl/terasic_mtl_syscons.c, which has the following
note that shows my analysis to be not inaccurate but incorrect:

/*
 * XXXRW: For historical reasons, syscons can't register video consoles
 * without a keyboard implementation.  Provide a dummy.
 */

As far as I can tell, this isn't the case anymore as sckbdprobe's
return value is ignored and other references to the keyboard appear to
be properly gated on sc->keyboard being valid.

I only have a single machine that can run syscons, but I built a
kernel with the same modifications to remove all of the keyboard
drivers (-ukbd, kbdmux, hyperv) for that machine and encountered no
problems in practice.

I will proceed with removing the last dummy driver and MFC as scheduled.

Thanks,

Kyle Evans