Re: [PATCH] tiny-printf: Add support for upper case hex values

["Michael Walle" <mwalle@kernel.org>]

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Hi,

> > I wouldn't mind printing the pointer for %p[mMI], but %pa prints the
> > *content* of the pointer which is really confusing. I.e. in
> > pinctrl-single.c the reg value pairs are printed like
> > 
> >   dev_dbg(dev, "reg/val %pa/0x%08x\n", &reg, val);
> > 
> > with reg being a pointer to a physical address. So with tiny_printf
> > the address of reg (which is a pointer to the stack) is printed in
> > this case.
> > 
> > I don't think we can print %p without putting more logic into the
> > decoding. I think the culprit here is the fallthrough to %x, which
> > then leads to the confusing behavior shown above. IMHO if we want to
> > avoid that, we'd have to make %p entirely unsupported.
> > 
> > diff --git a/lib/tiny-printf.c b/lib/tiny-printf.c
> > index faf55d7f327..8147ffa2c1b 100644
> > --- a/lib/tiny-printf.c
> > +++ b/lib/tiny-printf.c
> > @@ -269,21 +269,18 @@ static int _vprintf(struct printf_info *info, const char *fmt,
> > va_list va)
> >  						div_out(info, &num, div);
> >  				}
> >  				break;
> > +#if CONFIG_IS_ENABLED(NET) || CONFIG_IS_ENABLED(NET_LWIP) || _DEBUG
>
> What if we fine-tune tinyprinf via config here?
> For example SPL_USE_TINY_PRINTF_POINTER_SUPPORT and
> select it by NET or NET_LWIP. If someone needs it,
> the pointer output can be enabled, otherwise '?' for
> unsupported is output.

Yeah I had a similar idea, but I'm not sure if yet another config
symbol is worth it. That's up to the maintainer to decide :)

In any case, we have a different behavior to what is printed
right now, as we drop the fallthrough to %x. Tom? Simon?

-michael

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