diff options
Diffstat (limited to '0012-bootsplash.patch')
| -rw-r--r-- | 0012-bootsplash.patch | 363 |
1 files changed, 321 insertions, 42 deletions
diff --git a/0012-bootsplash.patch b/0012-bootsplash.patch index e8cd479312be..e5c1fd0c8604 100644 --- a/0012-bootsplash.patch +++ b/0012-bootsplash.patch @@ -1,42 +1,321 @@ -diff --git a/drivers/tty/vt/keyboard.c b/drivers/tty/vt/keyboard.c -index f4166263bb3a..a248429194bb 100644 ---- a/drivers/tty/vt/keyboard.c -+++ b/drivers/tty/vt/keyboard.c -@@ -47,6 +47,8 @@ - - #include <asm/irq_regs.h> - -+#include <linux/bootsplash.h> -+ - extern void ctrl_alt_del(void); - - /* -@@ -1353,6 +1355,28 @@ static void kbd_keycode(unsigned int keycode, int down, int hw_raw) - } - #endif - -+ /* Trap keys when bootsplash is shown */ -+ if (bootsplash_would_render_now()) { -+ /* Deactivate bootsplash on ESC or Alt+Fxx VT switch */ -+ if (keycode >= KEY_F1 && keycode <= KEY_F12) { -+ bootsplash_disable(); -+ -+ /* -+ * No return here since we want to actually -+ * perform the VT switch. -+ */ -+ } else { -+ if (keycode == KEY_ESC) -+ bootsplash_disable(); -+ -+ /* -+ * Just drop any other keys. -+ * Their effect would be hidden by the splash. -+ */ -+ return; -+ } -+ } -+ - if (kbd->kbdmode == VC_MEDIUMRAW) { - /* - * This is extended medium raw mode, with keys above 127 +diff --git a/Documentation/ABI/testing/sysfs-platform-bootsplash b/Documentation/ABI/testing/sysfs-platform-bootsplash +new file mode 100644 +index 000000000000..742c7b035ded +--- /dev/null ++++ b/Documentation/ABI/testing/sysfs-platform-bootsplash +@@ -0,0 +1,11 @@ ++What: /sys/devices/platform/bootsplash.0/enabled ++Date: Oct 2017 ++KernelVersion: 4.14 ++Contact: Max Staudt <mstaudt@suse.de> ++Description: ++ Can be set and read. ++ ++ 0: Splash is disabled. ++ 1: Splash is shown whenever fbcon would show a text console ++ (i.e. no graphical application is running), and a splash ++ file is loaded. +diff --git a/Documentation/bootsplash.rst b/Documentation/bootsplash.rst +new file mode 100644 +index 000000000000..611f0c558925 +--- /dev/null ++++ b/Documentation/bootsplash.rst +@@ -0,0 +1,285 @@ ++==================== ++The Linux bootsplash ++==================== ++ ++:Date: November, 2017 ++:Author: Max Staudt <mstaudt@suse.de> ++ ++ ++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. ++ ++Purely compiling in the bootsplash will not render it functional - to actually ++render a splash, you will also need a splash theme file. See the example ++utility and script in ``tools/bootsplash`` for a live demo. ++ ++ ++ ++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 keeping ``/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 ++ ++ ++ ++Command line arguments ++====================== ++ ++``bootsplash.bootfile`` ++ Which file in the initramfs to load. ++ ++ The splash theme is loaded via request_firmware(), thus to load ++ ``/lib/firmware/bootsplash/mytheme`` pass the command line: ++ ++ ``bootsplash.bootfile=bootsplash/mytheme`` ++ ++ Note: The splash file *has to be* in the initramfs, as it needs to be ++ available when the splash is initialized early on. ++ ++ Default: none, i.e. a non-functional splash, falling back to showing text. ++ ++ ++ ++sysfs run-time configuration ++============================ ++ ++``/sys/devices/platform/bootsplash.0/enabled`` ++ Enable/disable the bootsplash. ++ The system boots with this set to 1, but will not show a splash unless ++ a splash theme file is also loaded. ++ ++ ++ ++Kconfig ++======= ++ ++``BOOTSPLASH`` ++ Whether to compile in bootsplash support ++ (depends on fbcon compiled in, i.e. ``FRAMEBUFFER_CONSOLE=y``) ++ ++ ++ ++Bootsplash file format ++====================== ++ ++A file specified in the kernel configuration as ``CONFIG_BOOTSPLASH_FILE`` ++or specified on the command line as ``bootsplash.bootfile`` will be loaded ++and displayed as soon as fbcon is initialized. ++ ++ ++Main blocks ++----------- ++ ++There are 3 main blocks in each file: ++ ++ - one File header ++ - n Picture headers ++ - m (Blob header + payload) blocks ++ ++ ++Structures ++---------- ++ ++The on-disk 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``" on big-endian platforms ++ (the reverse on little endian) ++ - The file format version (for incompatible updates, hopefully never) ++ - The background color ++ - Number of picture and blob blocks ++ - Animation speed (we only allow one delay 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. ++ ++ ++Alignment ++--------- ++ ++The bootsplash file is designed to be loaded into memory as-is. ++ ++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. ++ ++ ++Further information ++------------------- ++ ++Please see ``drivers/video/fbdev/core/bootsplash_file.h`` for further ++details and possible values in the file. ++ ++ ++ ++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. ++ ++ ++ ++FAQ: Frequently Asked Questions ++=============================== ++ ++I want to see the log! How do I show the log? ++--------------------------------------------- ++ ++Press ESC while the splash is shown, or remove the ``bootsplash.bootfile`` ++parameter from the kernel cmdline. Without that parameter, the bootsplash ++will boot disabled. ++ ++ ++Why use FB instead of modern DRM/KMS? ++------------------------------------- ++ ++This is a semantic problem: ++ - What memory to draw the splash to? ++ - And what mode will the screen be set to? ++ ++Using the fbdev emulation solves these issues. ++ ++Let's start from a bare KMS system, without fbcon, and without fbdev ++emulation. In this case, as long as userspace doesn't open the KMS ++device, the state of the screen is undefined. No framebuffer is ++allocated in video RAM, and no particular mode is set. ++ ++In this case, we'd have to allocate a framebuffer to show the splash, ++and set our mode ourselves. This either wastes a screenful of video RAM ++if the splash is to co-exist with the userspace program's own allocated ++framebuffer, or there is a flicker as we deactivate and delete the ++bootsplash's framebuffer and hand control over to userspace. Since we ++may set a different mode than userspace, we'd also have flicker due ++to mode switching. ++ ++This logic is already contained in every KMS driver that performs fbdev ++emulation. So we might as well use that. And the correct API to do so is ++fbdev. Plus, we get compatibility with old, pure fbdev drivers for free. ++With the fbdev emulation, there is *always* a well-defined framebuffer ++to draw on. And the selection of mode has already been done by the ++graphics driver, so we don't need to reinvent that wheel, either. ++Finally, if userspace decides to use /dev/fbX, we don't have to worry ++about wasting video RAM, either. ++ ++ ++Why is the bootsplash integrated in fbcon? ++------------------------------------------ ++ ++Right now, the bootsplash is drawn from within fbcon, as this allows us ++to easily know *when* to draw - i.e. when we're safe from fbcon and ++userspace drawing all over our beautiful splash logo. ++ ++Separating them is not easy - see the to-do list below. ++ ++ ++ ++TO DO list for future development ++================================= ++ ++Second enable/disable switch for the system ++------------------------------------------- ++ ++It may be helpful to differentiate between the system and the user ++switching off the bootsplash. Thus, the system may make it disappear and ++reappear e.g. for a password prompt, yet once the user has pressed ESC, ++it could stay gone. ++ ++ ++Fix buggy DRM/KMS drivers ++------------------------- ++ ++Currently, the splash code manually checks for fbdev emulation provided by ++the ast, cirrus, and mgag200 DRM/KMS drivers. ++These drivers use a manual mechanism similar to deferred I/O for their FB ++emulation, and thus need to be manually flushed onto the screen in the same ++way. ++ ++This may be improved upon in several ways: ++ ++1. Changing these drivers to expose the fbdev BO's memory directly, like ++ bochsdrmfb does. ++2. Creating a new fb_ops->fb_flush() API to allow the kernel to flush the ++ framebuffer once the bootsplash has been drawn into it. ++ ++ ++Separating from fbcon ++--------------------- ++ ++Separating these two components would yield independence from fbcon being ++compiled into the kernel, and thus lowering code size in embedded ++applications. ++ ++To do this cleanly will involve a clean separation of users of an FB device ++within the kernel, i.e. fbcon, bootsplash, and userspace. Right now, the ++legacy fbcon code and VT code co-operate to switch between fbcon and ++userspace (by setting the VT into KD_GRAPHICS mode). Installing a muxer ++between these components ensues refactoring of old code and checking for ++correct locking. +diff --git a/MAINTAINERS b/MAINTAINERS +index 5c237445761e..7ffac272434e 100644 +--- a/MAINTAINERS ++++ b/MAINTAINERS +@@ -2709,6 +2709,8 @@ BOOTSPLASH + M: Max Staudt <mstaudt@suse.de> + L: linux-fbdev@vger.kernel.org + S: Maintained ++F: Documentation/ABI/testing/sysfs-platform-bootsplash ++F: Documentation/bootsplash.rst + F: drivers/video/fbdev/core/bootsplash*.* + F: drivers/video/fbdev/core/dummycon.c + F: include/linux/bootsplash.h |