[U-Boot] ctrl-c detection (on 4xx platforms)

[Matthias Fuchs <matthias.fuchs@esd-electronics.com>]

Hi Wolfgang,

On Friday 12 September 2008 11:08:51 Wolfgang Denk wrote:
> Dear Matthias Fuchs,
>
> In message <200809120955.10866.matthias.fuchs@esd-electronics.com> you 
wrote:
> > when I disable CONFIG_AUTOBOOT_KEYED ctrl-c checking is not disabled.
>
> I think there is one "dis" ot "not" too many.
:-)
>
> > We are using CONFIG_AUTOBOOT_KEYED to have a special key (SPACE) to
> > abort autoboot and not the 'any' key.
>
> I thought so.
>
> > Is there any special reason why ctrl-c checking is disabled for
> > CONFIG_AUTOBOOT_KEYED?
>
> Excellent question. Next question, please.
>
>
> I think the rationale behind this is to prevent users from getting an
> interactive  prompt  by  just  pressing  ^C  -   the   intention   of
> CONFIG_AUTOBOOT_KEYED  is  similar to a login with password - without
> the correct password you are denied access to an  interactive  inter-
> face.
I see. This makes sense.
>
> But if you could use ^C as soon as the bootcmd  has  started  -  what
> should  happen  next?  We cannot simply drop you into the interactive
> shell?
Ok, this will cancel the whole mechanism. 

I only want to allow the space key to abort autoboot. With serial console 
cables connected (with no PC on the other side) you sometimes receive some
noise characters because of crosstalk. These chars will stop autoboot -> not 
good! We did never see this when restricting the stopkey to the space key.

Because I only need to abort my special bootcmd during testing I reenabled
ctrl-c checking in my loadpci command. 

Thanks for pointing out the ..KEYED philosophy.

Matthias
>
> Best regards,
>
> Wolfgang Denk