Re: [PATCH 00/10] fbcon,fonts: Refactor framebuffer console rotation

[Helge Deller <deller@gmx.de>]

Hi Thomas,

On 3/27/26 13:49, Thomas Zimmermann wrote:
> Refactor the framebuffer console rotation into individual components
> for glyphs, fonts and the overall fbcon state. Right now this is mixed
> up in fbcon_rotate.{c,h}. Also build cursor rotation on top of the new
> interfaces.
> 
> Start with an OOB fix in patch 1. If buffer allocation fails, fbcon
> currently uses a too-small glyph buffer for output. Avoid that.
> 
> Patches 2 to 4 make a number of small improvements to the font library
> and its callers.
> 
> Patches 5 to 8 refactor the font rotation. Fbcon rotation rotates each
> individual glphy in a font buffer and uses the rotated buffer's glyphs
> for output. The result looks like the console buffer has been rotated
> as a whole. Split this into helpers that rotate individual glyphs and
> a helper that rotates the font buffer of these. Then reimplement fbcon
> rotation on top. Document the public font helpers.
> 
> Patch 9 rebuilds cursor rotation on top of the new glyph helpers. The
> fbcon cursor is itself a glyph that has to be rotated in sync with the
> font.
> 
> Patch 10 moves the state of fbcon rotation into a single place and makes
> is a build-time conditional.
> 
> Tested with fbcon under bochs on Qemu.
> 
> Built upon the fbcon changes at [1].
> 
> [1] https://lore.kernel.org/linux-fbdev/20260309141723.137364-1-tzimmermann@suse.de/


Thanks a lot for this cleanup work!

I've applied this series to the fbdev git tree.

Helge

  
> Thomas Zimmermann (10):
>    fbcon: Avoid OOB font access if console rotation fails
>    vt: Implement helpers for struct vc_font in source file
>    lib/fonts: Provide helpers for calculating glyph pitch and size
>    lib/fonts: Clean up Makefile
>    lib/fonts: Implement glyph rotation
>    lib/fonts: Refactor glyph-pattern helpers
>    lib/fonts: Refactor glyph-rotation helpers
>    lib/fonts: Implement font rotation
>    fbcon: Fill cursor mask in helper function
>    fbcon: Put font-rotation state into separate struct
> 
>   drivers/tty/vt/vt.c                     |  34 +++
>   drivers/video/fbdev/core/bitblit.c      |  35 +--
>   drivers/video/fbdev/core/fbcon.c        |  48 ++++-
>   drivers/video/fbdev/core/fbcon.h        |  14 +-
>   drivers/video/fbdev/core/fbcon_ccw.c    |  70 ++----
>   drivers/video/fbdev/core/fbcon_cw.c     |  70 ++----
>   drivers/video/fbdev/core/fbcon_rotate.c |  88 ++------
>   drivers/video/fbdev/core/fbcon_rotate.h |  71 ------
>   drivers/video/fbdev/core/fbcon_ud.c     |  67 ++----
>   include/linux/console_struct.h          |  30 +--
>   include/linux/font.h                    |  51 +++++
>   lib/fonts/Makefile                      |  36 ++--
>   lib/fonts/font_rotate.c                 | 275 ++++++++++++++++++++++++
>   lib/fonts/fonts.c                       |   2 +-
>   14 files changed, 525 insertions(+), 366 deletions(-)
>   create mode 100644 lib/fonts/font_rotate.c
>