Re: [PATCH v2 03/13] vt: Store font in struct vc_font

[Helge Deller <deller@gmx.de>]

On 3/2/26 15:08, Thomas Zimmermann wrote:
> Replace struct console_font with struct vc_font for the type of the
> vc_font field of struct vc_data. Struct console_font is UAPI, which
> prevents further changes. Hence a new data type is required.
> 
> Struct console_font has a documented vertical pitch of 32 bytes. This
> is not the case after the font data has been loaded into the kernel.
> Changing the type of vc_font addresses this inconsistency.
> 
> The font data is now declared as constant, as it might come from the
> kernel's read-only section. There's some fallout throughout the console
> code where non-const variables refer to it. Fix them. A later update
> will declare the font data to a dedicated data type.
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---
>   drivers/video/fbdev/core/bitblit.c | 11 +++++------
>   drivers/video/fbdev/core/fbcon.c   |  4 ++--
>   drivers/video/fbdev/core/fbcon.h   |  4 ++--
>   include/linux/console_struct.h     | 29 +++++++++++++++++++++++++++--
>   4 files changed, 36 insertions(+), 12 deletions(-)
> 
....
> diff --git a/include/linux/console_struct.h b/include/linux/console_struct.h
> index ebdb9750d348..7fdcae6ed49c 100644
> --- a/include/linux/console_struct.h
> +++ b/include/linux/console_struct.h
> @@ -13,8 +13,9 @@
>   #ifndef _LINUX_CONSOLE_STRUCT_H
>   #define _LINUX_CONSOLE_STRUCT_H
>   
> -#include <linux/wait.h>
> +#include <linux/math.h>
>   #include <linux/vt.h>
> +#include <linux/wait.h>
>   #include <linux/workqueue.h>
>   
>   struct uni_pagedict;
> @@ -58,6 +59,30 @@ struct vc_state {
>   	bool		reverse;
>   };
>   
> +/**
> + * struct vc_font - Describes a font
> + * @width: The width of a single glyph in bits
> + * @height: The height of a single glyph in scanlines
> + * @charcount: The number of glyphs in the font
> + * @data: The raw font data
> + *
> + * Font data is organized as an array of glyphs. Each glyph is a bitmap with
> + * set bits indicating the foreground color. Unset bits indicate background
> + * color. The fields @width and @height store a single glyph's number of
> + * horizontal bits and vertical scanlines. If width is not a multiple of 8,
> + * there are trailing bits to fill up the byte. These bits should not be drawn.
> + *
> + * The field @data points to the first glphy's first byte. The value @charcount
> + * gives the number of glyphs in the font. There are no empty scanlines between
> + * two adjacent glyphs.
> + */
> +struct vc_font {
> +	unsigned int width;
> +	unsigned int height;
> +	unsigned int charcount;

I wonder if we shouldn't declare width and height as "u8" or "short int" type?
And charcount as u16 or "short int" ?
Makes later calculations shorter & easier.

Helge