구차니의 잡동사니 모음

Key terms

The X window system has nuanced usage of a number of terms when compared to common usage, particularly "display" and "screen", a subset of which is given here for convenience:

device

A graphics device such as a computer graphics card or a computer motherboard's integrated graphics chipset.

monitor

A physical device such as a CRT or a flat screen computer display.

screen

An area into which graphics may be rendered, either through software alone into system memory as with VNC, or within a graphics device, some of which can render into more than one screen simultaneously, either viewable simultaneously or interchangeably. Interchangeable screens are often set up to be notionally left and right from one another, flipping from one to the next as the mouse pointer reaches the edge of the monitor.

virtual screen

Two different meanings are associated with this term:

A technique allowing panning a monitor around a screen running at a larger resolution than the monitor is currently displaying.

An effect simulated by a window manager by maintaining window position information in a larger coordinate system than the screen and allowing panning by simply moving the windows in response to the user.

display

A collection of screens, often involving multiple monitors, generally configured to allow the mouse to move the pointer to any position within them. Linux-based workstations are usually capable of having multiple displays, among which the user can switch with a special keyboard combination such as control-alt-function-key, simultaneously flipping all the monitors from showing the screens of one display to the screens in another.

The term "display" should not be confused with the more specialized jargon "Zaphod display". The latter is a rare configuration allowing multiple users of a single computer to each have an independent set of display, mouse, and keyboard, as though they were using separate computers, but at a lower per-seat cost.

[링크 : https://en.wikipedia.org/wiki/X_Window_System] 

Display Names

From the user's perspective, every X server has a display name of the form:

hostname:displaynumber.screennumber

This information is used by the application to determine how it should connect to the server and which screen it should use by default (on displays with multiple monitors):

hostname

The hostname specifies the name of the machine to which the display is physically connected. If the hostname is not given, the most efficient way of communicating to a server on the same machine will be used.

displaynumber

The phrase "display" is usually used to refer to collection of monitors that share a common keyboard and pointer (mouse, tablet, etc.). Most workstations tend to only have one keyboard, and therefore, only one display. Larger, multi-user systems, however, frequently have several displays so that more than one person can be doing graphics work at once. To avoid confusion, each display on a machine is assigned a display number (beginning at 0) when the X server for that display is started. The display number must always be given in a display name.

screennumber

Some displays share a single keyboard and pointer among two or more monitors. Since each monitor has its own set of windows, each screen is assigned a screen number (beginning at 0) when the X server for that display is started. If the screen number is not given, screen 0 will be used.

[링크 : http://linux.die.net/man/7/x] 

pi@raspberrypi /usr/share/X11/xorg.conf.d $ cat 99-fbturbo.conf

# and load xf86-video-fbturbo driver installed in the system.

#

# When troubleshooting, check /var/log/Xorg.0.log for the debugging

# output and error messages.

#

# Run "man fbturbo" to get additional information about the extra

# configuration options for tuning the driver.

Section "Device"

        Identifier      "rpi"

        Driver          "fbturbo"

        Option          "fbdev" "/dev/fb0"

        Option          "SwapbuffersWait" "true"

EndSection

Section "Device"

        Identifier      "spi"

        Driver          "fbturbo"

        Option          "fbdev" "/dev/fb1"

        Option          "SwapbuffersWait" "true"

EndSection

Section "InputClass"

        Identifier      "calibration"

        MatchProduct    "ADS7846 Touchscreen"

        Option          "Calibration"   "237 3965 3888 214"

        Option          "SwapAxes"      "1"

        Option          "InvertX" "1"

        Option          "InvertY" "1"

EndSection

Section "Monitor"

        Identifier      "rpi hdmi"

EndSection

Section "Monitor"

        Identifier      "rpi spi"

EndSection

Section "Screen"

        Identifier      "primary"

        Device          "rpi"

        Monitor         "rpi hdmi"

EndSection

Section "Screen"

        Identifier      "secondary"

        Device          "spi"

        Monitor         "rpi spi"

EndSection

Section "ServerLayout"

        Identifier      "default"

        Screen 0        "primary" 0 0

        Screen 1        "secondary" LeftOf "primary"

        Option          "Xinerama" "1"

EndSection 

top - 15:07:12 up 3 min,  1 user,  load average: 0.93, 0.48, 0.19

Tasks: 111 total,   1 running, 110 sleeping,   0 stopped,   0 zombie

%Cpu(s):  2.2 us,  1.7 sy,  0.0 ni, 94.1 id,  2.1 wa,  0.0 hi,  0.0 si,  0.0 st

KiB Mem:    884380 total,   309792 used,   574588 free,    18640 buffers

KiB Swap:   102396 total,        0 used,   102396 free,   154808 cached

  PID USER      PR  NI  VIRT  RES  SHR S  %CPU %MEM    TIME+  COMMAND           

 2555 root      20   0 53280  28m  16m S   5.3  3.3   0:14.19 Xorg              

 2810 pi        20   0 98852  20m  17m S   2.6  2.4   0:02.61 lxterminal        

 2695 pi        20   0  128m  26m  22m S   2.3  3.0   0:03.67 lxpanel           

 2830 pi        20   0  391m 128m  67m S   2.0 14.9   1:15.68 epiphany-browse   

 2899 pi        20   0  4496 2416 2060 R   0.7  0.3   0:00.74 top               

    1 root      20   0  2148 1244 1140 S   0.3  0.1   0:00.86 init              

    6 root      20   0     0    0    0 D   0.3  0.0   0:00.63 kworker/u8:0      

 2197 nobody    20   0  2024 1468 1352 S   0.3  0.2   0:00.38 thd               

 2693 pi        20   0 21080  12m 9052 S   0.3  1.4   0:01.62 openbox           

 2703 root      20   0     0    0    0 S   0.3  0.0   0:00.44 kworker/u8:3      

 2909 pi        20   0 89712  18m  15m S   0.3  2.1   0:00.88 leafpad           

    2 root      20   0     0    0    0 S   0.0  0.0   0:00.00 kthreadd          

    3 root      20   0     0    0    0 S   0.0  0.0   0:00.13 ksoftirqd/0       

    4 root      20   0     0    0    0 S   0.0  0.0   0:00.00 kworker/0:0       

    5 root       0 -20     0    0    0 S   0.0  0.0   0:00.00 kworker/0:0H      

    7 root      20   0     0    0    0 S   0.0  0.0   0:00.36 rcu_preempt       

    8 root      20   0     0    0    0 S   0.0  0.0   0:00.00 rcu_sched          

$ irrecord /storage/.config/lircd.conf

[링크 : http://wiki.openelec.tv/index.php?title=Guide_To_lirc_rpi_GPIO_Receiver] 

$ cat lircd.conf

# Please make this file available to others

# by sending it to <lirc@bartelmus.de>

#

# this config file was automatically generated

# using lirc-0.9.1-git(default) on Tue Aug 11 02:51:10 2015

#

# contributed by

#

# brand:                       /storage/lircd.conf

# model no. of remote control:

# devices being controlled by this remote:

#

begin remote

  name  /storage/.config/lircd.conf

  bits           16

  flags SPACE_ENC|CONST_LENGTH

  eps            30

  aeps          100

  header       9085  4524

  one           646  1604

  zero          646   490

  ptrail        646

  pre_data_bits   16

  pre_data       0xFF

  gap          108567

  toggle_bit_mask 0x0

      begin codes

          KEY_UP                   0x7A85

          KEY_DOWN                 0x1AE5

          KEY_LEFT                 0x609F

          KEY_RIGHT                0x20DF

          KEY_OK                   0x9A65

          KEY_PLAY                 0xE01F

          KEY_FASTFORWARD          0x42BD

          KEY_STOP                 0x629D

          KEY_MENU                 0xC03F

          KEY_EXIT                 0x50AF

          KEY_VOLUMEUP             0xA25D

          KEY_VOLUMEDOWN           0x22DD

       end codes

end remote 

$ sudo mv /usr/share/X11/xorg.conf.d/99-fbturbo.conf ~

$ sudo nano /usr/share/X11/xorg.conf.d/99-pitft.conf

Section "Device"

  Identifier "Adafruit PiTFT"

  Driver "fbdev"

  Option "fbdev" "/dev/fb1"

EndSection

$ sudo raspi-config

Then pick the Enable Boot to Desktop/Scratch option and choose if you want to boot to the console, desktop, or scratch environment.  

/etc/X11/xorg.conf.d/99-calibration.conf

Option "EmulateThirdButton" "1"

Option "EmulateThirdButtonTimeout" "750"

Option "EmulateThirdButtonMoveThreshold" "30"

So for example your file will look like:

Section "InputClass"

   Identifier      "calibration"

   MatchProduct    "stmpe-ts"

   Option  "Calibration"   "3800 120 200 3900"

   Option  "SwapAxes"      "1"

   Option "EmulateThirdButton" "1"

   Option "EmulateThirdButtonTimeout" "750"

   Option "EmulateThirdButtonMoveThreshold" "30"

EndSection 

dtoverlay=pitft28r,rotate=90,speed=62000000,fps=25

Or whatever you like for speed, rotation, and frames-per-second. BUT, here's the thing, the Pi only supports a fixed number of SPI frequencies. So tweaking the number a little won't do anything. The kernel will round the number to the closest value. You will always get frequencies that are 250MHz divided by an even number. Here's the only SPI frequencies this kernel supports

15,625,000 (a.k.a 16000000 = 16 MHz)

17,857,142 (a.k.a. 18000000 = 18 MHz)

20,833,333 (a.k.a 21000000 = 21 MHz)

25,000,000 (= 25 MHz)

31,250,000 (a.k.a 32000000 = 32MHz)

41,666,666 (a.k.a 42000000 = 42MHz)

62,500,000 (a.k.a 62000000 = 62MHz) 

use videocore GPU command  to switch off or on HDMI service thus saving valuable watts :)

Switch on

“/opt/vc/bin/tvservice -p”

Switch off

“/opt/vc/bin/tvservice -o”