Documentation/fb/framebuffer.rst

9 ---------------
13 software to access the graphics hardware through a well-defined interface, so
14 the software doesn't need to know anything about the low-level (hardware
22 --------------------------
39     /dev/fb0current -> fb0
40     /dev/fb1current -> fb1
50 graphics card in addition to the built-in hardware. The corresponding frame
69 --------------------------------
82   - You can request unchangeable information about the hardware, like name,
86   - You can request and change variable information about the hardware, like
92   - You can get and set parts of the color map. Communication is done with 16
114 --------------------------------------
126 ---------------
132   - If the `Display` subsection for the `fbdev` driver in the /etc/XF86Config
144   - Therefore it's also possible to specify resolutions in the /etc/XF86Config
145     file. This allows for on-the-fly resolution switching while retaining the
149     specify the timings in a different format (but `fbset -x` may help).
156 ---------------------
177     1/(28.37516E6 Hz) = 35.242E-9 s
181     640*35.242E-9 s = 22.555E-6 s
186     (640+272)*35.242E-9 s = 32.141E-6 s
190     1/(32.141E-6 s) = 31.113E3 Hz
195     (480+49)*32.141E-6 s = 17.002E-3 s
199     1/(17.002E-3 s) = 58.815 Hz
217   +----------+---------------------------------------------+----------+-------+
221   +----------###############################################----------+-------+
228   |<-------->#<---------------+--------------------------->#<-------->|<----->|
242   +----------###############################################----------+-------+
246   +----------+---------------------------------------------+----------+-------+
250   +----------+---------------------------------------------+----------+-------+
253 (in picoseconds, 1E-12 s), and vertical timings in number of scanlines.
257 --------------------------------------------------------------------
266   - pixclock: pixel clock in ps (pico seconds)
267   - left_margin: time from sync to picture
268   - right_margin: time from picture to sync
269   - upper_margin: time from sync to picture
270   - lower_margin: time from picture to sync
271   - hsync_len: length of horizontal sync
272   - vsync_len: length of vertical sync
284    left_margin = HFL - SH2
286    right_margin = SH1 - HR
288    hsync_len = SH2 - SH1
292    upper_margin = VFL - SV2
294    lower_margin = SV1 - VR
296    vsync_len = SV2 - SV1
303 -------------
306 applications, please refer to the Linux-fbdev website:
308     http://linux-fbdev.sourceforge.net/
312   - The manual pages for fbset: fbset(8), fb.modes(5)
313   - The manual pages for XFree86: XF68_FBDev(1), XF86Config(4/5)
314   - The mighty kernel sources:
316       - linux/drivers/video/
317       - linux/include/linux/fb.h
318       - linux/include/video/
323 ---------------
326 linux-fbdev@vger.kernel.org.
328 Point your web browser to http://sourceforge.net/projects/linux-fbdev/ for
333 --------------
337     ftp://ftp.uni-erlangen.de/pub/Linux/LOCAL/680x0/
343     http://www.linux-fbdev.org/
347 -----------
350 `X-framebuffer.README` by Roman Hodek and Martin Schaller. Section 6 was