mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-10-30 08:02:30 +00:00
63 lines
2 KiB
ReStructuredText
63 lines
2 KiB
ReStructuredText
|
Frame Buffer Library
|
||
|
|
====================
|
||
|
|
|
||
|
|
The frame buffer drivers depend heavily on four data structures. These
|
||
|
|
structures are declared in include/linux/fb.h. They are fb_info,
|
||
|
|
fb_var_screeninfo, fb_fix_screeninfo and fb_monospecs. The last
|
||
|
|
three can be made available to and from userland.
|
||
|
|
|
||
|
|
fb_info defines the current state of a particular video card. Inside
|
||
|
|
fb_info, there exists a fb_ops structure which is a collection of
|
||
|
|
needed functions to make fbdev and fbcon work. fb_info is only visible
|
||
|
|
to the kernel.
|
||
|
|
|
||
|
|
fb_var_screeninfo is used to describe the features of a video card
|
||
|
|
that are user defined. With fb_var_screeninfo, things such as depth
|
||
|
|
and the resolution may be defined.
|
||
|
|
|
||
|
|
The next structure is fb_fix_screeninfo. This defines the properties
|
||
|
|
of a card that are created when a mode is set and can't be changed
|
||
|
|
otherwise. A good example of this is the start of the frame buffer
|
||
|
|
memory. This "locks" the address of the frame buffer memory, so that it
|
||
|
|
cannot be changed or moved.
|
||
|
|
|
||
|
|
The last structure is fb_monospecs. In the old API, there was little
|
||
|
|
importance for fb_monospecs. This allowed for forbidden things such as
|
||
|
|
setting a mode of 800x600 on a fix frequency monitor. With the new API,
|
||
|
|
fb_monospecs prevents such things, and if used correctly, can prevent a
|
||
|
|
monitor from being cooked. fb_monospecs will not be useful until
|
||
|
|
kernels 2.5.x.
|
||
|
|
|
||
|
|
Frame Buffer Memory
|
||
|
|
-------------------
|
||
|
|
|
||
|
|
.. kernel-doc:: drivers/video/fbdev/core/fbmem.c
|
||
|
|
:export:
|
||
|
|
|
||
|
|
Frame Buffer Colormap
|
||
|
|
---------------------
|
||
|
|
|
||
|
|
.. kernel-doc:: drivers/video/fbdev/core/fbcmap.c
|
||
|
|
:export:
|
||
|
|
|
||
|
|
Frame Buffer Video Mode Database
|
||
|
|
--------------------------------
|
||
|
|
|
||
|
|
.. kernel-doc:: drivers/video/fbdev/core/modedb.c
|
||
|
|
:internal:
|
||
|
|
|
||
|
|
.. kernel-doc:: drivers/video/fbdev/core/modedb.c
|
||
|
|
:export:
|
||
|
|
|
||
|
|
Frame Buffer Macintosh Video Mode Database
|
||
|
|
------------------------------------------
|
||
|
|
|
||
|
|
.. kernel-doc:: drivers/video/fbdev/macmodes.c
|
||
|
|
:export:
|
||
|
|
|
||
|
|
Frame Buffer Fonts
|
||
|
|
------------------
|
||
|
|
|
||
|
|
Refer to the file lib/fonts/fonts.c for more information.
|
||
|
|
|