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

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Message-ID: <4c716fd1-c989-4e48-9878-e7312fefc302@suse.de>
Date: Sat, 22 Nov 2025 11:52:29 +0100
From: Thomas Zimmermann <tzimmermann@...e.de>
To: Ard Biesheuvel <ardb@...nel.org>
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

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?

Best regards
Thomas


-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
GF: Jochen Jaser, Andrew McDonald, Werner Knoblich, (HRB 36809, AG Nürnberg)