[U-Boot] confused ... how do some CONFIG settings "implicitly" set others?

[U-Boot] confused ... how do some CONFIG settings "implicitly" set others?

[Robert P. J. Day]

  reading http://www.denx.de/wiki/view/DULG/UBootSplashScreen, and i
see:

"To enable splash screen support, you have to add a "#define
CONFIG_SPLASH_SCREEN" to your board configuration file. This will also
implicitly enable U-Boot Bitmap Support."

  "implicitly"?  how does that work?  from what i can see in
define2mk.sed, the transformation is straightforward and there are no
dependencies or selects as in the kernel Kconfig structure.  how does
setting splash screen implicitly set bitmap support?  what am i
missing?

rday
--

========================================================================
Robert P. J. Day                               Waterloo, Ontario, CANADA

            Linux Consulting, Training and Kernel Pedantry.

Web page:                                          http://crashcourse.ca
Twitter:                                       http://twitter.com/rpjday
========================================================================

[U-Boot] confused ... how do some CONFIG settings "implicitly" set others?

[Wolfgang Denk]

Dear "Robert P. J. Day",

In message <alpine.LFD.2.00.0911200826340.27923@localhost> you wrote:
> 
>   reading http://www.denx.de/wiki/view/DULG/UBootSplashScreen, and i
> see:
> 
> "To enable splash screen support, you have to add a "#define
> CONFIG_SPLASH_SCREEN" to your board configuration file. This will also
> implicitly enable U-Boot Bitmap Support."
> 
>   "implicitly"?  how does that work?  from what i can see in
> define2mk.sed, the transformation is straightforward and there are no
> dependencies or selects as in the kernel Kconfig structure.  how does
> setting splash screen implicitly set bitmap support?  what am i
> missing?

Simple. The relevant parts of the code use

	#if defined(CONFIG_CMD_BMP) || defined(CONFIG_SPLASH_SCREEN)

so they get selected when CONFIG_CMD_BMP and/or CONFIG_SPLASH_SCREEN
is defined.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Heavier than air flying machines are impossible.
                    -- Lord Kelvin, President, Royal Society, c. 1895

[U-Boot] confused ... how do some CONFIG settings "implicitly" set others?

[Robert P. J. Day]

On Fri, 20 Nov 2009, Wolfgang Denk wrote:

> Dear "Robert P. J. Day",
>
> In message <alpine.LFD.2.00.0911200826340.27923@localhost> you wrote:
> >
> >   reading http://www.denx.de/wiki/view/DULG/UBootSplashScreen, and i
> > see:
> >
> > "To enable splash screen support, you have to add a "#define
> > CONFIG_SPLASH_SCREEN" to your board configuration file. This will also
> > implicitly enable U-Boot Bitmap Support."
> >
> >   "implicitly"?  how does that work?  from what i can see in
> > define2mk.sed, the transformation is straightforward and there are no
> > dependencies or selects as in the kernel Kconfig structure.  how does
> > setting splash screen implicitly set bitmap support?  what am i
> > missing?
>
> Simple. The relevant parts of the code use
>
> 	#if defined(CONFIG_CMD_BMP) || defined(CONFIG_SPLASH_SCREEN)
>
> so they get selected when CONFIG_CMD_BMP and/or CONFIG_SPLASH_SCREEN
> is defined.

  ok, i get it, but that's not "implicit," that's *explicit*.
totally different meaning.

rday
--


========================================================================
Robert P. J. Day                               Waterloo, Ontario, CANADA

            Linux Consulting, Training and Kernel Pedantry.

Web page:                                          http://crashcourse.ca
Twitter:                                       http://twitter.com/rpjday
========================================================================