[maemo-leste] [PATCH] bootmenu: Allow to quit it via CTRL+C

[Pali Rohár]

On Saturday 26 December 2020 23:32:27 Pavel Machek wrote:
> On Sat 2020-12-26 20:15:40, Pali Rohár wrote:
> > On Saturday 26 December 2020 20:10:10 Heinrich Schuchardt wrote:
> > > Am 26. Dezember 2020 20:03:56 MEZ schrieb "Pali Rohár" <pali at kernel.org>:
> > > >On Saturday 26 December 2020 19:44:23 Heinrich Schuchardt wrote:
> > > >> Am 26. Dezember 2020 19:02:25 MEZ schrieb "Pali Rohár"
> > > ><pali at kernel.org>:
> > > >> >When CTRL+C is pressed interrupt bootmenu and jump into U-Boot
> > > >console.
> > > >> >As the last entry in bootmenu is always U-Boot console just choose
> > > >the
> > > >> >last
> > > >> >entry when CTRL+C is pressed.
> > > >> >
> > > >> >It is useful when bootmenu is part of boot process and you want to
> > > >> >interrupt boot process by scripts which control U-Boot (serial)
> > > >> >console.
> > > >> 
> > > >> Wouldn't the escape key be a better choice?
> > > >
> > > >I can add also escape key. But has escape key stable ANSI sequence
> > > >which
> > > >is needed to catch? If you tell me which bytes to catch (for escape
> > > >key)
> > > >I will add it.
> > > 
> > > 0x1b is Escape
> > 
> > Does not work. 0x1b is not escape key. It is start of the ANSI escape
> > sequence which matches also existing keys up and down.
> 
> Unfortunately, 0x1b _is_ escape key. That is long standing bug of
> vt100 terminal.

Ok. And has xterm (or other terminals) somehow fixed it? Should we
expect that some other terminals send something different for ESC key?

> Usually timeout is used for detection. 0x1b followed by delay is
> escape key; 0x1b followed by [ is some other key.

Any idea how long timeout should be used for this detection?

Heinrich wrote in his patch that sequence of 0x1b 0x1b should be handled
by escape key. Does it mean that we need to handle both 0x1b+timeout and
also 0x1b+0x1b as a escape key? Or we should handle 0x1b+timeout or 0x1
followed by any non '[' character as escape key?


Anyway, this bootmenu was initially written for Nokia N900 (used on LCD
display with integrated keyboard) and this device does not have ESC key.
So I would like to have CTRL+C in bootmenu working independently of ESC
key support.