arch,sysfb: Move screen and edid info into single place

[PATCH 0/6] arch,sysfb: Move screen and edid info into single place

Posted by Thomas Zimmermann 1 week, 3 days ago

Replace screen_info and edid_info with sysfb_primary_device of type
struct sysfb_display_info. Update all users.

Sysfb DRM drivers currently fetch the global edid_info directly, when
they should get that information together with the screen_info from their
device. Wrapping screen_info and edid_info in sysfb_primary_display and
passing this to drivers enables this.

Replacing both with sysfb_primary_display has been motivate by the EFI
stub. EFI wants to transfer EDID via config table in a single entry.
Using struct sysfb_display_info this will become easily possible. Hence
accept some churn in architecture code for the long-term improvements.

Patches 1 and 2 reduce the exposure of screen_info in EFI-related code.

Patch 3 adds struct sysfb_display_info.

Patch 4 replaces scren_info with sysfb_primary_display. This results in
several changes throught the kernel, but is really just a refactoring.

Patch 5 updates sysfb to transfer sysfb_primary_display to the related
drivers.

Patch 6 moves edid_info into sysfb_primary_display. This resolves some
drivers' reference to the global edid_info, but also makes the EDID data
available on non-x86 architectures.

The short-term benefit of this series is in patches 5 and 6. With
sysfb_primary_display in place a follow-up series will improve EFI support
for EDID as outlined in the series at [1] and [2].

[1] https://lore.kernel.org/dri-devel/20251015160816.525825-1-tzimmermann@suse.de/
[2] https://lore.kernel.org/linux-efi/20251119123011.1187249-5-ardb+git@google.com/

Thomas Zimmermann (6):
  efi: earlycon: Reduce number of references to global screen_info
  efi: sysfb_efi: Reduce number of references to global screen_info
  sysfb: Add struct sysfb_display_info
  sysfb: Replace screen_info with sysfb_primary_display
  sysfb: Pass sysfb_primary_display to devices
  sysfb: Move edid_info into sysfb_primary_display

 arch/arm64/kernel/image-vars.h                |  2 +-
 arch/loongarch/kernel/efi.c                   | 11 +--
 arch/loongarch/kernel/image-vars.h            |  2 +-
 arch/riscv/kernel/image-vars.h                |  2 +-
 arch/x86/kernel/kexec-bzimage64.c             |  4 +-
 arch/x86/kernel/setup.c                       | 16 ++--
 arch/x86/video/video-common.c                 |  4 +-
 drivers/firmware/efi/earlycon.c               | 42 +++++-----
 drivers/firmware/efi/efi-init.c               | 14 ++--
 drivers/firmware/efi/libstub/efi-stub-entry.c | 18 +++--
 drivers/firmware/efi/sysfb_efi.c              | 81 ++++++++++---------
 drivers/firmware/sysfb.c                      | 13 +--
 drivers/firmware/sysfb_simplefb.c             |  2 +-
 drivers/gpu/drm/sysfb/efidrm.c                | 14 ++--
 drivers/gpu/drm/sysfb/vesadrm.c               | 14 ++--
 drivers/hv/vmbus_drv.c                        |  6 +-
 drivers/pci/vgaarb.c                          |  4 +-
 drivers/video/Kconfig                         |  1 -
 drivers/video/fbdev/core/fbmon.c              |  8 +-
 drivers/video/fbdev/efifb.c                   | 10 ++-
 drivers/video/fbdev/vesafb.c                  | 10 ++-
 drivers/video/fbdev/vga16fb.c                 |  8 +-
 drivers/video/screen_info_pci.c               |  5 +-
 include/linux/screen_info.h                   |  2 -
 include/linux/sysfb.h                         | 23 ++++--
 include/video/edid.h                          |  4 -
 26 files changed, 177 insertions(+), 143 deletions(-)


base-commit: 57e807d4454add8b60e8807ad1cf812141f34cdb
-- 
2.51.1

Re: [PATCH 0/6] arch,sysfb: Move screen and edid info into single place

Posted by Arnd Bergmann 1 week, 3 days ago

On Fri, Nov 21, 2025, at 14:36, Thomas Zimmermann wrote:
> Replace screen_info and edid_info with sysfb_primary_device of type
> struct sysfb_display_info. Update all users.
>
> Sysfb DRM drivers currently fetch the global edid_info directly, when
> they should get that information together with the screen_info from their
> device. Wrapping screen_info and edid_info in sysfb_primary_display and
> passing this to drivers enables this.
>
> Replacing both with sysfb_primary_display has been motivate by the EFI
> stub. EFI wants to transfer EDID via config table in a single entry.
> Using struct sysfb_display_info this will become easily possible. Hence
> accept some churn in architecture code for the long-term improvements.

This all looks good to me,

Acked-by: Arnd Bergmann <arnd@arndb.de>

It should also bring us one step closer to eventually
disconnecting the x86 boot ABI from the kernel-internal
sysfb_primary_display.

    Arnd

Re: [PATCH 0/6] arch,sysfb: Move screen and edid info into single place

Posted by Ard Biesheuvel 1 week, 3 days ago

On Fri, 21 Nov 2025 at 16:10, Arnd Bergmann <arnd@arndb.de> wrote:
>
> On Fri, Nov 21, 2025, at 14:36, Thomas Zimmermann wrote:
> > Replace screen_info and edid_info with sysfb_primary_device of type
> > struct sysfb_display_info. Update all users.
> >
> > Sysfb DRM drivers currently fetch the global edid_info directly, when
> > they should get that information together with the screen_info from their
> > device. Wrapping screen_info and edid_info in sysfb_primary_display and
> > passing this to drivers enables this.
> >
> > Replacing both with sysfb_primary_display has been motivate by the EFI
> > stub. EFI wants to transfer EDID via config table in a single entry.
> > Using struct sysfb_display_info this will become easily possible. Hence
> > accept some churn in architecture code for the long-term improvements.
>
> This all looks good to me,
>
> Acked-by: Arnd Bergmann <arnd@arndb.de>
>
> It should also bring us one step closer to eventually
> disconnecting the x86 boot ABI from the kernel-internal
> sysfb_primary_display.
>

Agreed

Acked-by: Ard Biesheuvel <ardb@kernel.org>

I can take patches 1-2 right away, if that helps during the next cycle.