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Date:   Wed, 2 Aug 2023 16:43:52 +0000
From:   "Dr. David Alan Gilbert" <linux@treblig.org>
To:     Randy Dunlap <rdunlap@infradead.org>
Cc:     Michael Ellerman <mpe@ellerman.id.au>, npiggin@gmail.com,
        christophe.leroy@csgroup.eu, sam@ravnborg.org,
        benh@kernel.crashing.org, linuxppc-dev@lists.ozlabs.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] powerpc: Use shared font data
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* Randy Dunlap (rdunlap@infradead.org) wrote:
> 
> 
> On 8/2/23 05:19, Michael Ellerman wrote:
> > "Dr. David Alan Gilbert" <linux@treblig.org> writes:
> >> * Michael Ellerman (mpe@ellerman.id.au) wrote:
> >>> linux@treblig.org writes:
> >>>> From: "Dr. David Alan Gilbert" <linux@treblig.org>
> >>>>
> >>>> PowerPC has a 'btext' font used for the console which is almost identical
> >>>> to the shared font_sun8x16, so use it rather than duplicating the data.
> >>>>
> >>>> They were actually identical until about a decade ago when
> >>>>    commit bcfbeecea11c ("drivers: console: font_: Change a glyph from
> >>>>                         "broken bar" to "vertical line"")
> >>>>
> >>>> which changed the | in the shared font to be a solid
> >>>> bar rather than a broken bar.  That's the only difference.
> >>>>
> >>>> This was originally spotted by PMD which noticed that sparc does
> >>>
> >>> PMD means "Page Middle Directory" to most Linux folks, I assume that's
> >>> not what you meant :)
> >>
> >> Ah, any good TLA is ripe for reuse:
> >>    https://pmd.github.io/pmd/pmd_userdocs_cpd.html
> > 
> > Thanks.
> > 
> > Unfortunately this patch causes a warning:
> > 
> >   WARNING: unmet direct dependencies detected for FONT_SUN8x16
> >     Depends on [n]: FONT_SUPPORT [=y] && FRAMEBUFFER_CONSOLE [=y] && (!SPARC && FONTS [=n] || SPARC)
> >     Selected by [y]:
> >     - BOOTX_TEXT [=y] && PPC_BOOK3S [=y]
> > 
> > And breaks allmodconfig with:
> > 
> >   ld: arch/powerpc/kernel/btext.o:(.toc+0x0): undefined reference to `font_sun_8x16'
> >   make[3]: *** [../scripts/Makefile.vmlinux:36: vmlinux] Error 1
> > 
> > I guess the Kconfig logic needs some more work.
> 
> Also please see:
>   https://lore.kernel.org/all/dd29e5f5-d9f7-0103-e602-b98f26c88fb1@infradead.org/
> for a similar problem on UML.

Thanks Michael, Randy.

Does anyone understand why the font_sun8x16 has any of those
 'Depends on' ?

It's just a font structure definition.

Dave

> -- 
> ~Randy
-- 
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