Source: linux Severity: wishlist Dear Maintainer,
Currently, Debian does not enable CONFIG_DRM_SIMPLEDRM or CONFIG_FRAMEBUFFER_CONSOLE_DEFERRED_TAKEOVER by default. I'd like to request that these config options be enabled for UEFI-enabled architectures in order to better support flicker-free boot. CONFIG_DRM_SIMPLEDRM enables a simple DRM driver for platform-provided framebuffers. The driver is primarily useful for lightweight graphics handling before heavier drivers have loaded (such as NVIDIA or AMD drivers) and vendor-agnostic early-boot framebuffer handling. Specifically, this is the default choice for early-boot splash programs like Plymouth. Using SimpleDRM removes the need for the system administrator to explicitly load any vendor-specific modules in the initrd or increase timeouts in Plymouth to compensate for longer load times of larger drivers. CONFIG_FRAMEBUFFER_CONSOLE_DEFERRED_TAKEOVER defers the clearing of the framebuffer console until the first text is displayed on the console. Without this option, there is a brief time between the firmware splash screen and the initialization Plymouth splash screen where the kernel may clear the graphics from the firmware. When booting with "quiet", this will result in a black flicker between the UEFI firmware and Plymouth. Without "quiet", text output is briefly visible as expected. By enabling the deferred takeover, the graphics from the firmware can remain in the framebuffer until either a) the kernel begins printing text or b) Plymouth (or similar software) takes control and does whatever it's been configured to do. In cases where flicker-free boot is desired, that would typically be reusing the BGRT graphics in the framebuffer and overlaying or augmenting it with additional elements like a loading spinner. SimpleDRM is not a hard requirement for flicker-free boot, but it does help significantly when building configurations not tied to a single vendor. Deferred takeover, on the other hand, is required for the aforementioned reasons. Other distributions have already used both options for a while in stable configurations (Fedora, NixOS, Red Hat, OpenSUSE, Arch Linux, etc.), so I believe the change would be relatively low-impact. There were some concerns around combining GRUB and deferred takeover, but I believe that was fixed back in 2018 by Fedora. -- System Information: Debian Release: 13.2 APT prefers stable-updates APT policy: (500, 'stable-updates'), (500, 'stable-security'), (500, 'stable') Architecture: amd64 (x86_64) Kernel: Linux 6.12.57+deb13-amd64 (SMP w/2 CPU threads; PREEMPT) Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=locale: Cannot set LC_ALL to default locale: No such file or directory UTF-8), LANGUAGE=en_US:en Shell: /bin/sh linked to /usr/bin/dash Init: systemd (via /run/systemd/system) LSM: AppArmor: enabled
