Re: [RFC] new APIs to use wskbd(4) input on non-wsdisplayttydevices

[Izumi Tsutsui <tsutsui%ceres.dti.ne.jp@localhost>]

uwe@ wrote:

> > On the other hand, news68k (and sun) machines have putchar()
> > that also handles virtual terminal ops like backspace, CR/LF,
> > and even scrolling at the bottom of screen. In this case
> > no VT emulation layer is necessary in the kernel side,
> > so kernel's putc(9) just calls firmware's putchar(),
> > and for userland processes we can simply pass translated
> > wskbd inputs to line discipline of the tty device.
> > 
> > That's the reason why I proposed to add register/deregister
> > APIs to pass wskbd data to romcons tty device.
> > 
> > What do you think about this case?
> 
> Add trivial wsemul_none (or wsemul_delegate, or whatever a suitable
> name might be) that does even less than wsemul_dumb and only ever uses
> putchar to pass chars to the firmware emulator?

I considered about it when I tried to implement news68k ROM console
driver, but I gave it up because:

- wscons(9) was the most complicated driver with undocumented APIs
  (struct wsemul_ops etc.)
- wsdisplay(9) would pull a lot of unnecessary sources like wsdisplay.c
  etc. (for screen ops) while TERM=wsvt25 could not be used
- there was no sample implementation using "putchar() with VT emulation"
- on the other hand there were simple implementation for PROM console
  functions (sys/arch/sun3/dev/kd.c and sys/dev/ofw/ofcons.c etc.)
  and actually it was quite simple to connect wskbd(4) to "romcons"
  driver

Thanks,
---
Izumi Tsutsui