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From: "Dr. David Alan Gilbert" <linux@treblig.org>
To: Sam Ravnborg <sam@ravnborg.org>
Cc: linux-kernel@vger.kernel.org, npiggin@gmail.com,
	linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH] powerpc: Use shared font data
Date: Tue, 25 Jul 2023 17:08:31 +0000	[thread overview]
Message-ID: <ZMABj6UNK98fONEQ@gallifrey> (raw)
In-Reply-To: <20230725170104.GA838289@ravnborg.org>

* Sam Ravnborg (sam@ravnborg.org) wrote:
> Hi David,
> 
> On Tue, Jul 25, 2023 at 01:01:41AM +0100, linux@treblig.org wrote:
> > 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
> > 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.
> > 
> > One difference I notice in PowerPC is that there are a bunch of compile
> > options for the .c files for the early code to avoid a bunch of security
> > compilation features;  it's not clear to me if this is a problem for
> > this font data.
> > 
> > Tested very lightly with a boot without FS in qemu.
> > 
> > Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
> 
> Yep, looks very similar to sparc, so
> 
> Reviewed-by: Sam Ravnborg <sam@ravnborg.org>

Thanks!

Dave

-- 
 -----Open up your eyes, open up your mind, open up your code -------   
/ Dr. David Alan Gilbert    |       Running GNU/Linux       | Happy  \ 
\        dave @ treblig.org |                               | In Hex /
 \ _________________________|_____ http://www.treblig.org   |_______/

WARNING: multiple messages have this Message-ID (diff)
From: "Dr. David Alan Gilbert" <linux@treblig.org>
To: Sam Ravnborg <sam@ravnborg.org>
Cc: mpe@ellerman.id.au, npiggin@gmail.com,
	christophe.leroy@csgroup.eu, benh@kernel.crashing.org,
	linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] powerpc: Use shared font data
Date: Tue, 25 Jul 2023 17:08:31 +0000	[thread overview]
Message-ID: <ZMABj6UNK98fONEQ@gallifrey> (raw)
In-Reply-To: <20230725170104.GA838289@ravnborg.org>

* Sam Ravnborg (sam@ravnborg.org) wrote:
> Hi David,
> 
> On Tue, Jul 25, 2023 at 01:01:41AM +0100, linux@treblig.org wrote:
> > 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
> > 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.
> > 
> > One difference I notice in PowerPC is that there are a bunch of compile
> > options for the .c files for the early code to avoid a bunch of security
> > compilation features;  it's not clear to me if this is a problem for
> > this font data.
> > 
> > Tested very lightly with a boot without FS in qemu.
> > 
> > Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
> 
> Yep, looks very similar to sparc, so
> 
> Reviewed-by: Sam Ravnborg <sam@ravnborg.org>

Thanks!

Dave

-- 
 -----Open up your eyes, open up your mind, open up your code -------   
/ Dr. David Alan Gilbert    |       Running GNU/Linux       | Happy  \ 
\        dave @ treblig.org |                               | In Hex /
 \ _________________________|_____ http://www.treblig.org   |_______/

  reply	other threads:[~2023-07-25 17:29 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-07-25  0:01 [PATCH] powerpc: Use shared font data linux
2023-07-25 17:01 ` Sam Ravnborg
2023-07-25 17:01   ` Sam Ravnborg
2023-07-25 17:08   ` Dr. David Alan Gilbert [this message]
2023-07-25 17:08     ` Dr. David Alan Gilbert
2023-07-28  3:44 ` Michael Ellerman
2023-07-28 10:39   ` Dr. David Alan Gilbert
2023-07-28 10:39     ` Dr. David Alan Gilbert
2023-08-02 12:19     ` Michael Ellerman
2023-08-02 12:19       ` Michael Ellerman
2023-08-02 14:44       ` Randy Dunlap
2023-08-02 14:44         ` Randy Dunlap
2023-08-02 16:43         ` Dr. David Alan Gilbert
2023-08-02 16:43           ` Dr. David Alan Gilbert

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