MFC r308312: vidcontrol: improve error handling in vt(4) font loading

PR: 209078

MFC r281581: vidcontrol: make size argument optional again for syscons

r273544 (MFC in r273921) changed the -f option allow no arguments in vt
mode (used to reset the font back to the default), but broke the
optionality of the size argument for syscons. Drop the required argument
from syscons' optstring for -f so the optional argument handler works
the same way for both syscons and vt.

Sponsored by: The FreeBSD Foundation

vt(4): Add PIO_VFONT_DEFAULT ioctl to restore the default builtin font

To restore the default font using vidcontrol(1), use the "-f" flag
without an argument:
vidcontrol -f < /dev/ttyv0

PR: 193910
Differential Revision: https://reviews.freebsd.org/D971
Submitted by: Marcin Cieslak <saper@saper.info>
Reviewed by: ray@, emaste@
Approved by: ray@
MFC of: r273544

267622 Log:
Rename vt(4) vga module to dismiss interference with syscons(4) vga module.
267623 Log:
Remove stale link to deleted vt(4) xboxfb driver.
267624 Log:
syscons(4) and vt(4) can be built together now.
267625 Log:
Allow to disable syscons(4) if "hw.syscons.disable" kenv is set.
267626 Log:
Suspend vt(4) initialization if "kern.vt.disable" kenv is set.
267965 by emaste@ Log:
Use a common tunable to choose between vt(4)/sc(4)
With this change and previous work from ray@ it will be possible to put
both in GENERIC, and have one enabled by default, but allow the other to
be selected via the loader.
(The previous implementation had separate kern.vt.disable and
hw.syscons.disable tunables, and would panic if both drivers were
compiled in and neither was explicitly disabled.)
268175 by emaste@ Log:
Fix vt(4) detection in kbdcontrol and vidcontrol
As sc(4) and vt(4) coexist and are both enabled in GENERIC, the existence
of a vt(4) sysctl is not sufficient to determine that vt(4) is in use.
Reported by: Trond Endrestøl
268045 by emaste@ Log:
Add vt(4) to GENERIC and retire the separate VT config
vt(4) and sc(4) can now coexist in the same kernel. To choose the vt
driver, set the loader tunable kern.vty=vt .

Sponsored by: The FreeBSD Foundation

MFC: 266836, 266839
vt(4) support for vidcontrol(1).
o Teach vidcontrol(1) how to load vt(4) font.
o Teach vidcontrol(1) to distinct which virtual terminal system is running now.
o Load vt(4) fonts from different location.
o Add $FreeBSD$ tag for path.h.
vt(4) support for kbdcontrol(1).
Enable kbdcontrol(1) to use maps from vt(4) keymaps dir /usr/share/vt/keymaps
if vt(4) is present.

Sponsored by: The FreeBSD Foundation

MFC r281581: vidcontrol: make size argument optional again for syscons

r273544 (MFC in r273921) changed the -f option allow no arguments in vt
mode (used to reset the font back to the default), but broke the
optionality of the size argument for syscons. Drop the required argument
from syscons' optstring for -f so the optional argument handler works
the same way for both syscons and vt.

Sponsored by: The FreeBSD Foundation

vt(4): Add PIO_VFONT_DEFAULT ioctl to restore the default builtin font

To restore the default font using vidcontrol(1), use the "-f" flag
without an argument:
vidcontrol -f < /dev/ttyv0

PR: 193910
Differential Revision: https://reviews.freebsd.org/D971
Submitted by: Marcin Cieslak <saper@saper.info>
Reviewed by: ray@, emaste@
Approved by: ray@
MFC of: r273544

267622 Log:
Rename vt(4) vga module to dismiss interference with syscons(4) vga module.
267623 Log:
Remove stale link to deleted vt(4) xboxfb driver.
267624 Log:
syscons(4) and vt(4) can be built together now.
267625 Log:
Allow to disable syscons(4) if "hw.syscons.disable" kenv is set.
267626 Log:
Suspend vt(4) initialization if "kern.vt.disable" kenv is set.
267965 by emaste@ Log:
Use a common tunable to choose between vt(4)/sc(4)
With this change and previous work from ray@ it will be possible to put
both in GENERIC, and have one enabled by default, but allow the other to
be selected via the loader.
(The previous implementation had separate kern.vt.disable and
hw.syscons.disable tunables, and would panic if both drivers were
compiled in and neither was explicitly disabled.)
268175 by emaste@ Log:
Fix vt(4) detection in kbdcontrol and vidcontrol
As sc(4) and vt(4) coexist and are both enabled in GENERIC, the existence
of a vt(4) sysctl is not sufficient to determine that vt(4) is in use.
Reported by: Trond Endrestøl
268045 by emaste@ Log:
Add vt(4) to GENERIC and retire the separate VT config
vt(4) and sc(4) can now coexist in the same kernel. To choose the vt
driver, set the loader tunable kern.vty=vt .

Sponsored by: The FreeBSD Foundation

MFC: 266836, 266839
vt(4) support for vidcontrol(1).
o Teach vidcontrol(1) how to load vt(4) font.
o Teach vidcontrol(1) to distinct which virtual terminal system is running now.
o Load vt(4) fonts from different location.
o Add $FreeBSD$ tag for path.h.
vt(4) support for kbdcontrol(1).
Enable kbdcontrol(1) to use maps from vt(4) keymaps dir /usr/share/vt/keymaps
if vt(4) is present.

Sponsored by: The FreeBSD Foundation