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Thu, 2 Apr 2026 11:00:14 -0400 (EDT) X-Mailer: MessagingEngine.com Webmail Interface Precedence: bulk X-Mailing-List: linux-fbdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ThreadId: ATYY62_w4Fts Date: Thu, 02 Apr 2026 16:59:52 +0200 From: "Arnd Bergmann" To: "Thomas Zimmermann" , "Javier Martinez Canillas" , "Ard Biesheuvel" , "Ilias Apalodimas" , "Huacai Chen" , "WANG Xuerui" , "Maarten Lankhorst" , "Maxime Ripard" , "Dave Airlie" , "Simona Vetter" , "K. Y. Srinivasan" , "Haiyang Zhang" , "Wei Liu" , "Dexuan Cui" , longli@microsoft.com, "Helge Deller" Cc: linux-arm-kernel@lists.infradead.org, loongarch@lists.linux.dev, linux-efi@vger.kernel.org, linux-riscv@lists.infradead.org, dri-devel@lists.freedesktop.org, linux-hyperv@vger.kernel.org, linux-fbdev@vger.kernel.org Message-Id: In-Reply-To: <3e466158-c2e5-4e23-934f-dcdbb71ad41f@suse.de> References: <20260402092305.208728-1-tzimmermann@suse.de> <20260402092305.208728-4-tzimmermann@suse.de> <78f76717-8f1e-41d6-92f7-261df96b84b6@app.fastmail.com> <3e466158-c2e5-4e23-934f-dcdbb71ad41f@suse.de> Subject: Re: [PATCH 3/8] firmware: sysfb: Make CONFIG_SYSFB a user-selectable option Content-Type: text/plain Content-Transfer-Encoding: 7bit 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