Re: [PATCH RFC v2 1/3] drm: client: add splash client

Maxime Ripard <[email protected]> Thu, 22 Jan 2026 14:36:56 +0100
Newsgroups	org.kernel.vger.linux-embedded,org.freedesktop.lists.dri-devel,org.kernel.vger.linux-doc,org.kernel.vger.linux-kernel
Message-ID	<20260122-scallop-of-original-domination-3a554a@houat>
Hi,

On Tue, Jan 06, 2026 at 03:25:40PM +0100, Francesco Valla wrote:
> Add a DRM client that draws a simple splash, with possibility to show:
> 
>   - a colored background;
>   - a static BMP image (loaded as firmware);
>   - the logo provided by EFI BGRT.
> 
> The client is not meant to replace a full-featured bootsplash, but
> rather to remove some complexity (and hopefully boot time) on small
> embedded platforms or on systems with a limited scope (e.g: recovery
> or manufacturing images).
> 
> The background color can be set either at build time from a dedicated
> config option or at runtime through the drm_client_lib.splash_color
> command line parameter. Any color in RGB888 format can be used.
> 
> If enabled, the static BMP image is loaded using the kernel firmware
> infrastructure; a valid BMP image with 24bpp color and no compression
> is expected. The name of the image can be set through the
> drm_client_lib.splash_bmp kernel command line parameter, with the
> default being 'drm_splash.bmp'.
> 
> Just like the existing DRM clients, the splash can be enabled from the
> kernel command line using drm_client_lib.active=splash.
> 
> Signed-off-by: Francesco Valla <[email protected]>
> ---
>  drivers/gpu/drm/clients/Kconfig               |  79 ++-
>  drivers/gpu/drm/clients/Makefile              |   1 +
>  drivers/gpu/drm/clients/drm_client_internal.h |   9 +
>  drivers/gpu/drm/clients/drm_client_setup.c    |   8 +
>  drivers/gpu/drm/clients/drm_splash.c          | 883 ++++++++++++++++++++++++++
>  5 files changed, 979 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/clients/Kconfig b/drivers/gpu/drm/clients/Kconfig
> index 6096c623d9d5b1a3d4a40d986c45aad2f8277767..dd8cd6cacd1166932eb3890dd816b9ae2d26330f 100644
> --- a/drivers/gpu/drm/clients/Kconfig
> +++ b/drivers/gpu/drm/clients/Kconfig
> @@ -12,6 +12,7 @@ config DRM_CLIENT_LIB
>  config DRM_CLIENT_SELECTION
>  	tristate
>  	depends on DRM
> +	select DRM_CLIENT_LIB if DRM_CLIENT_SPLASH
>  	select DRM_CLIENT_LIB if DRM_CLIENT_LOG
>  	select DRM_CLIENT_LIB if DRM_FBDEV_EMULATION
>  	help
> @@ -85,10 +86,79 @@ config DRM_CLIENT_LOG
>  	  If you only need logs, but no terminal, or if you prefer userspace
>  	  terminal, say "Y".
>  
> +config DRM_CLIENT_SPLASH
> +	bool "Display graphic splash"
> +	depends on DRM_CLIENT_SELECTION
> +	select DRM_CLIENT
> +	select DRM_CLIENT_SETUP
> +	select DRM_DRAW
> +	help
> +	  This enables a splash drm client, able to display either a plain
> +	  color or a static image until the userspace is ready to take over.
> +	  The splash will be displayed on all screens available at boot, if
> +	  any, or on the ones part of the first hotplug event.
> +
> +config DRM_CLIENT_SPLASH_BACKGROUND_COLOR
> +	hex "Splash background color"
> +	depends on DRM_CLIENT_SPLASH
> +	default 0x000000
> +	help
> +	  The default splash background color, in RGB888 format.
> +
> +	  The color can be overridden through the drm_client_lib.splash_color
> +	  kernel command line parameter.
> +
> +config DRM_CLIENT_SPLASH_BMP_SUPPORT
> +	bool
> +
> +choice
> +	prompt "Splash source"
> +	depends on DRM_CLIENT_SPLASH
> +	default DRM_CLIENT_SPLASH_SRC_COLOR
> +	help
> +	  Selects the source for the splash graphic.
> +
> +config DRM_CLIENT_SPLASH_SRC_COLOR
> +	bool "Solid color"
> +	help
> +	  Use a solid color as splash. The color is selected through the
> +	  DRM_CLIENT_SPLASH_BACKGROUND_COLOR config option.
> +
> +	  The image will be loaded using the firmware loading facility the
> +	  kernel provides.
> +
> +config DRM_CLIENT_SPLASH_SRC_BMP
> +	bool "BMP image"
> +	select DRM_CLIENT_SPLASH_BMP_SUPPORT
> +	select FW_LOADER
> +	help
> +	  Use a BMP (bitmap) image as splash. If the image is smaller than the
> +	  display(s), it will be centered and the color specified through the
> +	  DRM_CLIENT_SPLASH_BACKGROUND_COLOR config option will be used as
> +	  background.
> +
> +	  The image will be loaded using the firmware loading facility the
> +	  kernel provides; it shall use 24 bits per pixel and shall not be
> +	  compressed. The name of the file can be set through the
> +	  drm_client_lib.splash_bmp command line parameter, with the default
> +	  being 'drm_splash.bmp'.
> +
> +config DRM_CLIENT_SPLASH_SRC_BGRT
> +	bool "EFI BGRT"
> +	select DRM_CLIENT_SPLASH_BMP_SUPPORT
> +	depends on EFI
> +	help
> +	  Use the BGRT image provided by the EFI bootloader. If the image is
> +	  smaller than the display(s), it will be centered and the color
> +	  specified through the DRM_CLIENT_SPLASH_BACKGROUND_COLOR config
> +	  option will be used as background.
> +
> +endchoice

I'm not sure we should consider it a xor choice. If we do, that means
that it's effectively unusable by distros, since you don't know ahead of
time if the platform it's going to boot on will have a BGRT or not.

Trying BGRT, and then falling back to either an image or a solid
background would be easier to work with.

Maxime
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