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

Autor: Pavel Machek
Datum:
To: Pali Rohár
CC: Heinrich Schuchardt, maemo-leste, u-boot, Simon Glass, Thirupathaiah Annapureddy
Betreff: Re: [maemo-leste] [PATCH] bootmenu: Allow to quit it via CTRL+C

Hi!

> > > > >> >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?

Not really. Try it:

pavel@duo:~$ cat | hexdump -C
^[ahoj
00000000  1b 61 68 6f 6a 0a                                 |.ahoj.|
00000006

> > 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?

Yes, that makes some sense. 10msec would be right value for the
timeout, I'd say.

> 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.

Or maybe "q" is good choice for the bootmenu?

Best regards,
                                    Pavel
-- 
http://www.livejournal.com/~pavelmachek

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