Re: [PATCH 3/8] firmware: sysfb: Make CONFIG_SYSFB a user-selectable option

["Arnd Bergmann" <arnd@arndb.de>]

On Thu, Apr 2, 2026, at 16:10, Thomas Zimmermann wrote:
> Am 02.04.26 um 15:08 schrieb Arnd Bergmann:
>> On Thu, Apr 2, 2026, at 11:09, Thomas Zimmermann wrote:
>> I don't really like this part of the series and would prefer
>> to keep CONFIG_SYSFB hidden as much as possible as an x86
>> (and EFI) specific implementation detail, with the hope
>> of eventually seperating out the x86 bits from the EFI ones.
>
> You mean, you want to use the EFI-provided framebuffers without the 
> intermediate step of going through sysfb_primary_display?
>
> In that case, CONFIG_SYSFB would become an x86-internal thing, right?

The part that is still needed from sysfb is the arbitration
between DRM_EFI and the PCI device driver for the same hardware,
so I think some part of sysfb is clearly needed, in particular
the sysfb_disable() function that removes the EFI framebuffer
when there is a conflicting simpledrm or hardware specific
driver.

The parts that I want to keep out of that is anything
related to the x86 boot protocol, non-EFI framebuffers,
text console, and kexec handoff, which we don't need on
non-x86 UEFI systems.

I don't mind the idea of having a sysfb_primary_display
in the EFI code if that helps keep EFI sane on x86,
but it would be good to make that local to
drivers/firmware/efi and (eventually) detached from
include/uapi/linux/screen_info.h.

>> In general, I am always in favor of properly using Kconfig
>> dependencies over 'select' statements, for the same reasons
>> you describe, but I don't want the the x86 logic for
>> the legacy VESA and VGA console handling to leak into more
>> architectures than necessary.
>>
>> Do you think we could instead move the sysfb_init()
>> function into the same two places that contain the
>> sysfb_primary_display definition (arch/x86/kernel/setup.c,
>> drivers/firmware/efi/efi-init.c) and simplify the efi version
>> to take out the x86 bits? That would reduce the rest
>> of sysfb-primary.c to the logic to unregister the device,
>> and that could then be selected by both x86 and EFI.
>
> No, I'm more than happy that sysfb finally consolidates all the 
> init-framebuffer setup and detection that floated around in the kernel. 
> I would not want it to be duplicated again.
>
> For now, we could certainly keep CONFIG_SYSFB hidden and autoselected. 
> Although I think this will require soem sort of solution at a later point.

Can you clarify which problem you are trying to solve
with that?

     Arnd