Re: Surprising Kconfig depends semantics

[Adrian Bunk <bunk@fs.tum.de>]

On Fri, Aug 08, 2003 at 05:13:48PM +0200, Roman Zippel wrote:

> Hi,

Hi Roman,

> On Fri, 8 Aug 2003, Adrian Bunk wrote:
> 
> > CONFIG_SERIO=m with CONFIG_KEYBOARD_ATKBD=y shouldn't be a valid 
> > combination.
> > 
> > The correct solution is most likely a
> > 	default y if INPUT=y && INPUT_KEYBOARD=y && SERIO=y
> > 	default m if INPUT!=n && INPUT_KEYBOARD!=n && SERIO!=n
> 
> This is probably the easiest solution:
> 
> 	default INPUT_KEYBOARD && SERIO
> 
> (INPUT_KEYBOARD already depends on INPUT)

I'll send a
  default INPUT && INPUT_KEYBOARD && SERIO
patch (to address the things James said, in any cases it doesn't do any 
harm).

But it stays strange that a default can assign a value that isn't 
allowed by the depends, and you therefore have to write the depends 
twice in this case:

config KEYBOARD_ATKBD
        tristate "AT keyboard support" if EMBEDDED || !X86 
        default INPUT && INPUT_KEYBOARD && SERIO
        depends on INPUT && INPUT_KEYBOARD && SERIO


> > The semantics that in
> > 
> > config FOO
> > 	tristate
> > 	default y if BAR
> > 
> > FOO will be set to y if BAR=m is a bit surprising.
> 
> Why?

On a first thought I'd have expected it to be equivalent to
  default y if BAR=y

> bye, Roman

cu
Adrian

-- 

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       "Only a promise," Lao Er said.
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