Subject: Re: [PATCH] powerpc: Use shared font data

From: Michael Ellerman <[email-masked]>
Date: Wed, 02 Aug 2023 22:19:41 +1000

"Dr. David Alan Gilbert" <[email-masked]> writes:
> * Michael Ellerman ([email-masked]) wrote:
>> [email-masked] writes:
>> > From: "Dr. David Alan Gilbert" <[email-masked]>
>> >
>> > 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.

cheers