Latest revision as of 12:16, 18 January 2023

On this page you will find usefull informations to have a working Linux Framebuffer on your board.

Introduction

Linux Framebuffer is the lowest level (standardized) API for userspace programs to access video capabilities of the system you're running on. It allows you to directly "draw" your graphics in the video memory. Some higher level librairies can be put on top of the Framebuffer for more portability: SDL, Qt/Embedded, GTK, DirectFB, etc...

Kernel configuration

Note: Framebuffer is already configured (for Sharp LQ043 LCD on APF9328 and for Chimei LW700 on APF27/APF51) in standard/default Armadeus kernel image. APF28 has a boot option to choose the LCD.

Instructions to configure Linux kernel were moved to Talk:FrameBuffer and are only given as references or if you want to change the default LCD.

Userland

Framebuffer device can be accessed with /dev/fb0.

You can activate some tools from the Buildroot's menuconfig:

 $ make menuconfig

 Package Selection for the target
     ...
     Graphic libraries and applications (graphic/text)  ---> 
     ...
         [*] fbgrab
         [*] fbtest
         [*] fbv
     ...
        ---> Graphic libraries and applications (graphic/text)  
            ---> fbset/fbv/fbgrab

Note: As explain on LinuxInstall page, to compile fbtest, libnetpbm10-dev must be installed in your host system

For example to grab a snapshot of the framebuffer:

# fbgrab /tmp/snapshot.png

For example to display an image using standard image file formats PNG, GIF...:

# fbv myimage.png

Tips

Login/Console

To stop blinking cursor:

 # echo 0 > /sys/class/graphics/fbcon/cursor_blink

also possible at boot time (with 3.x recent kernels):

BIOS> setenv extrabootargs vt.global_cursor_default=0

To make it blinking again:

 # echo 1 > /sys/class/graphics/fbcon/cursor_blink

To have a login on LCD, add these line in /etc/inittab of your rootfs:

# Set up a getty on LCD
tty1::respawn:/sbin/getty 38400 tty1

Screenshot

To grab a screenshot of a running Framebuffer application, use FBGrab

Sleep

To enter in Framebuffer sleep mode:

 # echo 1 > /sys/class/graphics/fb0/blank

To leave Framebuffer sleep power mode:

 # echo 0 > /sys/class/graphics/fb0/blank

To set "sleep mode"/screensaver entering time (where X is a time in minute; 0 = never):

 # echo -e '\033[9;X]' > /dev/tty1    (from serial console)

or

 # echo -e '\033[9;X]'    (from framebuffer console)

or to set it at each boot, use /etc/inittab:

 tty1::sysinit:echo -e '\033[9;X]'

Other usefull ESC sequences

To (definitly) hide cursor:

 # echo -e '\033[?17;0;0c' > /dev/tty1    (from serial console)

or

 # echo -e '\033[?17;0;0c'    (from framebuffer console)

inverse screen on:

 # echo -e '\033[?5h' > /dev/tty1

inverse screen off:

 # echo -e '\033[?5l' > /dev/tty1

To erase the screen

echo -e '\033[2J' > /dev/tty1 (from serial console)

Links

@@ Line 1: / Line 1: @@
-== Armadeus Framebuffer documentation page ! ==
+On this page you will find usefull informations to have a working Linux Framebuffer on your board.
-Here is the procedure to have a working framebuffer on the board (beware
+==Introduction==
-it's tricky for the moment !!, but it's for people who can't wait ;-))
+Linux Framebuffer is the lowest level (standardized) API for userspace programs to access video capabilities of the system you're running on. It allows you to directly "draw" your graphics in the video memory.
+Some higher level librairies can be put on top of the Framebuffer for more portability: [[SDL]], [[Qt/Embedded]], GTK, DirectFB, etc...
+==Kernel configuration==
+{{Note | Framebuffer is already configured (for [[LQ043_Adapt|Sharp LQ043 LCD]] on [[APF9328]] and for Chimei LW700 on [[APF27]]/[[APF51]]) in standard/default Armadeus kernel image. [[APF28]] has a boot option to [[APF28Dev#Selecting_LCD|choose the LCD]].}}
-* comment lines number 427 & 438 in linux/drivers/video/imxfb.c (PD11,PD12 config)
+Instructions to configure Linux kernel were moved to [[Talk:FrameBuffer]] and are only given as references or if you want to change the default LCD.
-* merge attached scb9328.c file with linux/arc/arm/mach-imx/scb9328.c
-configure the linux kernel for Framebuffer support:
+==Userland==
-<pre>
+* Framebuffer device can be accessed with ''/dev/fb0''.
-make menuconfig
+* You can activate some tools from the Buildroot's menuconfig:
+<pre class="host">
+ $ make menuconfig
+</pre>
+<pre class="config">
+ Package Selection for the target
+     ...
+     Graphic libraries and applications (graphic/text)  --->
+     ...
+         [*] fbgrab
+         [*] fbtest
+         [*] fbv
+     ...
+        ---> Graphic libraries and applications (graphic/text)
+            ---> fbset/fbv/fbgrab
 </pre>
-* in "Char Devices" menu, activate ''"Virtual Terminal"'' and ''"Support for virtual terminal on console"''
-* in "Graphic support" activate "Support for Framebuffer", "Motorola iMX
-LCD support" "Console display driver support ->Frame buffer console
-support" (deactivate VGA stuff & add some fonts), then choose 224 colour
-boot logo
-recompile the kernel, now to have console on serial port, you will have
+{{Note | As explain on [[LinuxInstall]] page, to compile '''fbtest''', ''libnetpbm10-dev'' must be installed in your host system}}
-to add "console=ttySMX0,115200n8" to your boot parameters
-load image on your board and enjoy (you should see linux logo on screen
+* For example to grab a snapshot of the framebuffer:
-at startup)!
+<pre class="apf">
+# fbgrab /tmp/snapshot.png
+</pre>
-If you have devfs activated, framebuffer device can be accessed with /dev/fb/0. Otherwise, you will neede to create the device node with
+* For example to display an image using standard image file formats PNG, GIF...:
-<pre>
+<pre class="apf">
-mknod c 29 0
+# fbv myimage.png
 </pre>
-You can activate some test tools from the armadeus build process:
+==Tips==
-<pre>
-make menuconfig -> packages -> fbset
+===Login/Console===
+* To stop blinking cursor:
+<pre class="apf">
+ # echo 0 > /sys/class/graphics/fbcon/cursor_blink
+</pre>
+also possible at boot time (with 3.x recent kernels):
+<pre class="apf">
+BIOS> setenv extrabootargs vt.global_cursor_default=0
+</pre>
+* To make it blinking again:
+<pre class="apf">
+ # echo 1 > /sys/class/graphics/fbcon/cursor_blink
+</pre>
+* To have a login on LCD, add these line in /etc/inittab of your rootfs:
+<pre class="apf">
+# Set up a getty on LCD
+tty1::respawn:/sbin/getty 38400 tty1
 </pre>
-You have several test tools on yahoo groups to play a little with the framebuffer.
+===Screenshot===
+* To grab a screenshot of a running Framebuffer application, use [[FBGrab]]
+===Sleep===
+* To enter in Framebuffer sleep mode:
+<pre class="apf">
+ # echo 1 > /sys/class/graphics/fb0/blank
+</pre>
+* To leave Framebuffer sleep power mode:
+<pre class="apf">
+ # echo 0 > /sys/class/graphics/fb0/blank
+</pre>
+* To set "sleep mode"/screensaver entering time (where X is a time in minute; 0 = never):
+<pre class="apf">
+ # echo -e '\033[9;X]' > /dev/tty1    (from serial console)
+</pre>
+or
+<pre class="apf">
+ # echo -e '\033[9;X]'    (from framebuffer console)
+</pre>
+or to set it at each boot, use ''/etc/inittab'':
+<pre class="apf">
+ tty1::sysinit:echo -e '\033[9;X]'
+</pre>
+==Other usefull ESC sequences==
+* To (definitly) hide cursor:
+<pre class="apf">
+ # echo -e '\033[?17;0;0c' > /dev/tty1    (from serial console)
+</pre>
+or
+<pre class="apf">
+ # echo -e '\033[?17;0;0c'    (from framebuffer console)
+</pre>
+* inverse screen on:
+<pre class="apf">
+ # echo -e '\033[?5h' > /dev/tty1
+</pre>
+* inverse screen off:
+<pre class="apf">
+ # echo -e '\033[?5l' > /dev/tty1
+</pre>
+* To erase the screen
+<pre class="apf">
+echo -e '\033[2J' > /dev/tty1 (from serial console)
+</pre>
+=Links=
+* [[Linux_Boot_Logo|How to change the Linux boot logo]]
+* [[i.MX6 Framebuffer Overlay|How to play with Framebuffer overlay on APF6]]
+* [http://lxr.linux.no/linux/Documentation/VGA-softcursor.txt How to configure soft cursor]
+* http://linux-fbdev.sourceforge.net/
+* [http://www-curri.u-strasbg.fr/documentation/calcul/doc/ProPack/3SP1/docs/man_html/man4/console_codes.4.html Linux console ESC sequences]
+* http://directfb.org/
+* [http://docs.blackfin.uclinux.org/doku.php?id=linux-kernel:drivers:fbcon  Blackfin wiki page on the subject]
-[[Category:Documentation]]
+[[Category:Graphical User Interface]]
+[[Category:Framebuffer]]

Difference between revisions of "Framebuffer"

Latest revision as of 12:16, 18 January 2023

Contents

Introduction

Kernel configuration

Userland

Tips

Login/Console

Screenshot

Sleep

Other usefull ESC sequences

Links

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