Revision 6ae840e7cc4be0be3aa40d9f67c35c75cfc67d83 authored by Linus Torvalds on 15 December 2014, 00:43:47 UTC, committed by Linus Torvalds on 15 December 2014, 00:43:47 UTC
Pull char/misc driver updates from Greg KH: "Here's the big char/misc driver update for 3.19-rc1 Lots of little things all over the place in different drivers, and a new subsystem, "coresight" has been added. Full details are in the shortlog" * tag 'char-misc-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (73 commits) parport: parport_pc, do not remove parent devices early spmi: Remove shutdown/suspend/resume kernel-doc carma-fpga-program: drop videobuf dependency carma-fpga: drop videobuf dependency carma-fpga-program.c: fix compile errors i8k: Fix temperature bug handling in i8k_get_temp() cxl: Name interrupts in /proc/interrupt CXL: Return error to PSL if IRQ demultiplexing fails & print clearer warning coresight-replicator: remove .owner field for driver coresight: fixed comments in coresight.h coresight: fix typo in comment in coresight-priv.h coresight: bindings for coresight drivers coresight: Adding ABI documentation w1: support auto-load of w1_bq27000 module. w1: avoid potential u16 overflow cn: verify msg->len before making callback mei: export fw status registers through sysfs mei: read and print all six FW status registers mei: txe: add cherrytrail device id mei: kill cached host and me csr values ...
internals.txt
This is a first start for some documentation about frame buffer device
internals.
Geert Uytterhoeven <geert@linux-m68k.org>, 21 July 1998
James Simmons <jsimmons@user.sf.net>, Nov 26 2002
--------------------------------------------------------------------------------
*** STRUCTURES USED BY THE FRAME BUFFER DEVICE API ***
The following structures play a role in the game of frame buffer devices. They
are defined in <linux/fb.h>.
1. Outside the kernel (user space)
- struct fb_fix_screeninfo
Device independent unchangeable information about a frame buffer device and
a specific video mode. This can be obtained using the FBIOGET_FSCREENINFO
ioctl.
- struct fb_var_screeninfo
Device independent changeable information about a frame buffer device and a
specific video mode. This can be obtained using the FBIOGET_VSCREENINFO
ioctl, and updated with the FBIOPUT_VSCREENINFO ioctl. If you want to pan
the screen only, you can use the FBIOPAN_DISPLAY ioctl.
- struct fb_cmap
Device independent colormap information. You can get and set the colormap
using the FBIOGETCMAP and FBIOPUTCMAP ioctls.
2. Inside the kernel
- struct fb_info
Generic information, API and low level information about a specific frame
buffer device instance (slot number, board address, ...).
- struct `par'
Device dependent information that uniquely defines the video mode for this
particular piece of hardware.
--------------------------------------------------------------------------------
*** VISUALS USED BY THE FRAME BUFFER DEVICE API ***
Monochrome (FB_VISUAL_MONO01 and FB_VISUAL_MONO10)
-------------------------------------------------
Each pixel is either black or white.
Pseudo color (FB_VISUAL_PSEUDOCOLOR and FB_VISUAL_STATIC_PSEUDOCOLOR)
---------------------------------------------------------------------
The whole pixel value is fed through a programmable lookup table that has one
color (including red, green, and blue intensities) for each possible pixel
value, and that color is displayed.
True color (FB_VISUAL_TRUECOLOR)
--------------------------------
The pixel value is broken up into red, green, and blue fields.
Direct color (FB_VISUAL_DIRECTCOLOR)
------------------------------------
The pixel value is broken up into red, green, and blue fields, each of which
are looked up in separate red, green, and blue lookup tables.
Grayscale displays
------------------
Grayscale and static grayscale are special variants of pseudo color and static
pseudo color, where the red, green and blue components are always equal to
each other.
Computing file changes ...
