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

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Message-ID: <CAMj1kXHO12LritnbMXapGBV8QnQOCVopJbaBi2ejMUgZQFGdSg@mail.gmail.com>
Date: Sat, 22 Nov 2025 12:42:58 +0100
From: Ard Biesheuvel <ardb@...nel.org>
To: Thomas Zimmermann <tzimmermann@...e.de>
Cc: Arnd Bergmann <arnd@...db.de>, Javier Martinez Canillas <javierm@...hat.com>, x86@...nel.org, 
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org, 
	linux-efi@...r.kernel.org, loongarch@...ts.linux.dev, 
	linux-riscv@...ts.infradead.org, dri-devel@...ts.freedesktop.org, 
	linux-hyperv@...r.kernel.org, linux-pci@...r.kernel.org, 
	linux-fbdev@...r.kernel.org
Subject: Re: [PATCH 0/6] arch, sysfb: Move screen and edid info into single place

On Sat, 22 Nov 2025 at 11:52, Thomas Zimmermann <tzimmermann@...e.de> wrote:
>
> Hi
>
> Am 21.11.25 um 17:31 schrieb Ard Biesheuvel:
> > On Fri, 21 Nov 2025 at 17:26, Thomas Zimmermann <tzimmermann@...e.de> wrote:
> >> Hi
> >>
> >> Am 21.11.25 um 17:19 schrieb Ard Biesheuvel:
> >>> On Fri, 21 Nov 2025 at 17:09, Thomas Zimmermann <tzimmermann@...e.de> wrote:
> >>>>
> >>>> Am 21.11.25 um 17:08 schrieb Thomas Zimmermann:
> >>>>> Hi
> >>>>>
> >>>>> Am 21.11.25 um 16:56 schrieb Ard Biesheuvel:
> >>>>>> On Fri, 21 Nov 2025 at 16:53, Thomas Zimmermann <tzimmermann@...e.de>
> >>>>>> wrote:
> >>>>>>> Hi
> >>>>>>>
> >>>>>>> Am 21.11.25 um 16:16 schrieb Ard Biesheuvel:
> >>>>>>>> On Fri, 21 Nov 2025 at 16:10, Arnd Bergmann <arnd@...db.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@...db.de>
> >>>>>>> Thanks
> >>>>>>>
> >>>>>>>>> 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@...nel.org>
> >>>>>>> Thanks
> >>>>>>>
> >>>>>>>> I can take patches 1-2 right away, if that helps during the next
> >>>>>>>> cycle.
> >>>>>>>     From my sysfb-focused POV, these patches would ideally all go through
> >>>>>>> the same tree, say efi or generic arch, or whatever fits best. Most of
> >>>>>>> the other code is only renames anyway.
> >>>>>>>
> >>>>>> I don't mind queueing all of it, but I did get a conflict on
> >>>>>> drivers/pci/vgaarb.c
> >>>>> Probably from a78835b86a44 ("PCI/VGA: Select SCREEN_INFO on X86")
> >>>> https://lore.kernel.org/all/20251013220829.1536292-1-superm1@kernel.org/
> >>>>
> >>> Yes, if I merge back -rc2 first, I can apply patches 1-5 onto my
> >>> efi/next tree. But then I hit
> >>>
> >>> Applying: sysfb: Move edid_info into sysfb_primary_display
> >>> error: sha1 information is lacking or useless (drivers/gpu/drm/sysfb/efidrm.c).
> >>> error: could not build fake ancestor
> >>> Patch failed at 0006 sysfb: Move edid_info into sysfb_primary_display
> >>>
> >>> If you prefer, you can take the whole lot via the sysfb tree instead,
> >>> assuming it does not depend on the EDID changes I already queued up?
> >> Sure, I can also add it to the drm-misc tree. ETA in upstream would be
> >> v6.20-rc1.
> >>
> > But does that mean the EDID firmware on non-x86 will have to wait for
> > 6.21? I was trying to avoid making this a 6 month effort.
>
> No problem. Then let me rebase onto linux-next and put the existing EDID
> patches for EFI on top. It's mostly acked or reviewed already. Once we
> have it in good shape we can merged it all at once via the linux-efi
> tree. Does that work for you?
>

Sounds good.