linux-kernel - Re: [patch 3/3] VT: Bump font size limitation to 64x128 pixels

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Message-ID: <20221206204748.jvwr4jgtukkutrmb@begin>
Date:   Tue, 6 Dec 2022 21:47:48 +0100
From:   Samuel Thibault <samuel.thibault@...-lyon.org>
To:     Jiri Slaby <jirislaby@...nel.org>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        kbd@...ts.altlinux.org, linux-kernel@...r.kernel.org
Subject: Re: [patch 3/3] VT: Bump font size limitation to 64x128 pixels

Jiri Slaby, le mar. 06 déc. 2022 07:48:37 +0100, a ecrit:
> On 05. 12. 22, 1:07, Samuel Thibault wrote:
> > This moves 32x32 font size limitation checking down to drivers, so that
> > fbcon can allow large fonts.
> > 
> > We still keep a limitation to 64x128 pixels so as to have a simple bounded
> > allocation for con_font_get and in the userland kbd tool. That glyph size
> > will however be enough to have 128x36 characters on a "16/9 8K display".
> > 
> > Signed-off-by: Samuel Thibault <samuel.thibault@...-lyon.org>
> > 
> > Index: linux-6.0/drivers/tty/vt/vt.c
> > ===================================================================
> > --- linux-6.0.orig/drivers/tty/vt/vt.c
> > +++ linux-6.0/drivers/tty/vt/vt.c
> > @@ -4575,17 +4575,20 @@ void reset_palette(struct vc_data *vc)
> ...
> > -#define max_font_size 65536
> > +#define max_font_width	64
> > +#define max_font_height	128
> > +#define max_font_glyphs	512
> > +#define max_font_size	(max_font_glyphs*max_font_width*max_font_height)
> 
> So this is 64K -> 4M switch. We should likely convert to kvmalloc() too.

Oh, indeed, I'll fix that as well.

Thanks,
Samuel