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+What is the Linux bootsplash?
+==============================
+
+The Linux bootsplash is a graphical replacement for the 'quiet' boot option,
+typically showing a logo and a spinner animation as the system starts.
+
+Currently, it is a part of the Framebuffer Console support, and can be found
+as CONFIG_BOOTSPLASH in the kernel configuration. This means that as long as
+it is enabled, it hijacks fbcon's output and draws a splash screen instead.
+
+
+
+Motivation
+===========
+
+- The 'quiet' boot option only suppresses most messages during boot, but
+ errors are still shown.
+
+- A user space implementation can only show a logo once user space has been
+ initialized far enough to allow this. A kernel splash can display a splash
+ immediately as soon as fbcon can be displayed.
+
+- Implementing a splash screen in user space (e.g. Plymouth) is problematic
+ due to resource conflicts.
+
+ For example, if Plymouth is holding /dev/fb0 (provided via vesafb/efifb)
+ open, then most DRM drivers can't replace it because the address space is
+ still busy - thus leading to a VRAM reservation error.
+
+ See: https://bugzilla.opensuse.org/show_bug.cgi?id=980750
+
+
+
+Hooks - how the bootsplash is integrated
+=========================================
+
+drivers/video/fbdev/core/fbcon.c
+
+ fbcon_init() calls bootsplash_init(), which loads the default bootsplash
+ file or the one specified on the kernel command line.
+
+ fbcon_switch() draws the bootsplash when it's active, and is also one of
+ the callers of set_blitting_type().
+
+ set_blitting_type() calls fbcon_set_dummyops() when the bootsplash is
+ active, overriding the text rendering functions.
+
+ fbcon_cursor() will call bootsplash_disable() when an oops is being
+ printed in order to make a kernel panic visible.
+
+drivers/video/fbdev/core/dummyblit.c
+
+ This contains the dummy text rendering functions used to suppress text
+ output while the bootsplash is shown.
+
+drivers/tty/vt/keyboard.c
+
+ kbd_keycode() can call bootsplash_disable() when the user presses ESC
+ or F1-F12 (changing VT). This is to provide a built-in way of disabling
+ the splash manually at any time.
+
+drivers/tty/vt/vt_ioctl.c
+
+ vt_ioctl() will call bootsplash_disable() when a graphical application
+ such as the X server is started (i.e. when setting the VT to KD_GRAPHICS).
+
+
+
+Command line arguments
+=======================
+
+bool bootsplash.enable Whether to show a splash screen during boot
+ (default: off)
+
+string bootsplash.filename Which file in the initrd to load
+ (default: /bootsplash)
+
+
+
+sysfs run-time configuration
+=============================
+
+bool /sys/devices/platform/bootsplash.0/enabled Enable/disable
+
+trigger /sys/devices/platform/bootsplash.0/drop_splash Unload splash data
+ and free memory
+
+
+Kconfig
+========
+
+bool BOOTSPLASH Whether to compile in bootsplash support
+ (depends on fbcon compiled in, i.e.
+ FRAMEBUFFER_CONSOLE=y)
+
+string BOOTSPLASH_FILE Which file in the initrd to load
+ (default: /bootsplash)
+
+
+
+Bootsplash file format
+=======================
+
+A file specified in the kernel configuration as CONFIG_BOOTSPLASH_FILE or
+specified on the command line as bootsplash.filename will be loaded and
+displayed as soon as fbcon is initialized.
+
+
+There are 3 main blocks in each file:
+
+ - one File header
+ - n Picture headers
+ - m (Blob header + payload) blocks
+
+
+The structures are defined in drivers/video/fbdev/core/bootsplash_file.h
+and represent these blocks:
+
+ - struct splash_file_header
+
+ Represents the file header, with splash-wide information including:
+ -> The magic string "Linux bootsplash"
+ -> The file format version (for incompatible updates, hopefully never)
+ -> The background color
+ -> Number of picture and blob blocks
+ -> Animation speed (we only allow one speed for all animations)
+
+ The file header is followed by the first picture header.
+
+
+ - struct splash_picture_header
+
+ Represents an object (picture) drawn on screen, including its immutable
+ properties:
+ -> Width, height
+ -> Positioning relative to screen corners or in the center
+ -> Animation, if any
+ -> Animation type
+ -> Number of blobs
+
+ The picture header is followed by another picture header, up until n
+ picture headers (as defined in the file header) have been read. Then,
+ the (blob header, payload) pairs follow.
+
+
+ - struct splash_blob_header
+ (followed by payload)
+
+ Represents one raw data stream. So far, only picture data is defined.
+
+ The blob header is followed by a payload, then padding to n*16 bytes,
+ then (if further blobs are defined in the file header) a further blob
+ header.
+
+
+A note about alignment:
+
+The bootsplash file is designed to be loaded into memory as-is (plus
+performing an endianness conversion before further processing).
+
+All structures are a multiple of 16 bytes long, all elements therein are
+aligned to multiples of their length, and the payloads are always padded
+up to multiples of 16 bytes. This is to allow aligned accesses in all
+cases while still simply mapping the structures over an in-memory copy of
+the bootsplash file.
+
+
+Please see drivers/video/fbdev/core/bootsplash_file.h for further details and
+possible values in the file.