linux-kernel - Re: [PATCH v3] powerpc: Use shared font data

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Date:   Thu, 24 Aug 2023 20:01:53 +1000
From:   Michael Ellerman <mpe@...erman.id.au>
To:     "Dr. David Alan Gilbert" <linux@...blig.org>, npiggin@...il.com,
        christophe.leroy@...roup.eu, sam@...nborg.org,
        benh@...nel.crashing.org
Cc:     linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
        rdunlap@...radead.org
Subject: Re: [PATCH v3] powerpc: Use shared font data

"Dr. David Alan Gilbert" <linux@...blig.org> writes:
> * linux@...blig.org (linux@...blig.org) wrote:
>> From: "Dr. David Alan Gilbert" <linux@...blig.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 the PMF source code analyser, which
>> noticed that sparc does the same thing with the same data, and they
>> also share a bunch of functions to manipulate the data.  I've previously
>> posted a near identical patch for sparc.
>> 
>> Tested very lightly with a boot without FS in qemu.
>> 
>> Signed-off-by: Dr. David Alan Gilbert <linux@...blig.org>
>
> Hi Michael,
>   Just checking, is there anything else I need to do here?
   
I felt like the lib/fonts/Kconfig change could be cleaner, but the
existing Kconfig is not well structured for what we want to do.

I think at least it could be simplified to:

config FONT_SUN8x16
	bool "Sparc console 8x16 font"
	depends on (FRAMEBUFFER_CONSOLE && (FONTS || SPARC)) || BOOTX_TEXT


cheers


>> diff --git a/lib/fonts/Kconfig b/lib/fonts/Kconfig
>> index c035fde66aebe..1804abe08ffe4 100644
>> --- a/lib/fonts/Kconfig
>> +++ b/lib/fonts/Kconfig
>> @@ -98,7 +98,8 @@ config FONT_10x18
>>  
>>  config FONT_SUN8x16
>>  	bool "Sparc console 8x16 font"
>> -	depends on FRAMEBUFFER_CONSOLE && (!SPARC && FONTS || SPARC)
>> +	depends on (FRAMEBUFFER_CONSOLE || BOOTX_TEXT) &&\
>> +	           (!SPARC && FONTS || SPARC || PPC)
>>  	help
>>  	  This is the high resolution console font for Sun machines. Say Y.
>>