Re: [PATCH] powerpc: Use shared font data

From: Randy Dunlap
Date: Wed Aug 02 2023 - 10:45:17 EST




On 8/2/23 05:19, Michael Ellerman wrote:
> "Dr. David Alan Gilbert" <linux@xxxxxxxxxxx> writes:
>> * Michael Ellerman (mpe@xxxxxxxxxxxxxx) wrote:
>>> linux@xxxxxxxxxxx writes:
>>>> From: "Dr. David Alan Gilbert" <linux@xxxxxxxxxxx>
>>>>
>>>> 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@xxxxxxxxxxxxx/
for a similar problem on UML.

--
~Randy