diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-19 10:09:22 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-19 10:09:22 -0700 |
| commit | f4cdf7ca9a1fdcca413157df19753f388a5a224e (patch) | |
| tree | 60a31895b2446cd7fa27514e8c2843534a0de0da /Documentation/fb/internals.rst | |
| download | linux-stable-f4cdf7ca9a1fdcca413157df19753f388a5a224e.tar.gz linux-stable-f4cdf7ca9a1fdcca413157df19753f388a5a224e.zip | |
Merge tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-mediagrafted
Pull media updates from Mauro Carvalho Chehab:
- v4l2-core: added ISP statistics support and per-block validation
- v4l2-core: Allow unknown HDR10 white point and luminance
- New camera sensors: Sony IMX678 and IMX471m, Himax HM1092 IR sensor
- New codec: Milos: VPU v2.0 codec support
- isp driver: gained support for Dreamchip RPPX1 ISP framework
- vsp1 driver: gained support for RZ/T2H and RZ/N2H
- Novalake driver: gained CVS support for new NVL hardware
- dvb-core: fix feed leak on failed DMX_ADD_PID
- several driver fixes, cleanups and minor improvements
* tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (308 commits)
media: ipu-bridge: check all DMI entries when overriding sensor rotation
media: v4l2-async: avoid deleting unlinked ASC entry on link error
media: rzg2l-cru: Align bytesperline to hardware DMA stride requirement
media: intel/ipu6: fix async notifier cleanup leak on parse error
media: staging/ipu7: fix async notifier UAF on probe error path
media: amd: isp4: fix self-deadlock in isp4sd_pwron_and_init() error path
media: amd: isp4: release partial allocations in isp4if_alloc_fw_gpumem()
media: rcar-isp: Fix VSPX reference leaks
media: rcar-isp: Release ISPCORE resources
media: i2c: imx415: Release runtime PM reference on VBLANK error
media: i2c: imx415: Return test pattern write errors
media: renesas: vsp1: Declare index variables in for loop statement
media: renesas: vsp1: Make reset control optional to support platforms without a reset line
media: dt-bindings: media: renesas,vsp1: Document RZ/T2H and RZ/N2H SoCs
media: dt-bindings: media: renesas,fcp: Document RZ/T2H and RZ/N2H SoCs
media: nxp: imx8-isi: Add additional 32-bit RGB format support
media: nxp: imx8-isi: Add 16-bit raw Bayer format support
media: nxp: imx8-isi: Implement per-stream reference counting for multiplexed streams
media: nxp: imx8-isi: Use BIT_ULL() for 64-bit stream masks
media: nxp: imx8-isi: Correct color map between V4L2 and ISI
...
Diffstat (limited to 'Documentation/fb/internals.rst')
| -rw-r--r-- | Documentation/fb/internals.rst | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/Documentation/fb/internals.rst b/Documentation/fb/internals.rst new file mode 100644 index 000000000..696b50aa7 --- /dev/null +++ b/Documentation/fb/internals.rst @@ -0,0 +1,86 @@ +============================= +Frame Buffer device internals +============================= + +This is a first start for some documentation about frame buffer device +internals. + +Authors: + +- 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. |
