gsckbc —
GSC PS/2 keyboard and mouse interface
gsckbc* at gsc?
pckbd* at gsckbc?
pms* at gsckbc?
The gsckbc device is a machine dependent front end to
  the pckbport(9) interface.
  It attaches to the GSC PS/2 keyboard and mouse interface found in LASI chips.
  - gsckbc_attach: can't map I/O space
- The driver was not able to map the device registers during attachment. The
      device will not be usable.
- can't find master device
- An error occurred during attachment of the keyboard port so the mouse port
      can't be attached too.
Thegsckbc driver appeared in NetBSD
  2.0.
Actually the two PS/2 ports are a single device and share a single interrupt.
  The firmware lists them as individual devices in the firmware device tree.
  This illusion is kept to map the firmware device tree as close as possible to
  the kernel device tree. The first device is called master, gets the interrupt
  and the other is the slave. Assumption: Master attaches first, gets the
  interrupt and has lower HPA. So it is important that the master device,
  usually the keyboard port, attaches first to make the slave, usually the mouse
  port, usable.