Difference between revisions of "Framebuffer"
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==Kernel configuration== | ==Kernel configuration== | ||
| − | {{Note | Framebuffer is already configured (for [[LQ043_Adapt|Sharp LQ043 LCD]]) in standard/default Armadeus kernel image.}} | + | {{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.}} |
Following instructions are only given as references or if you want to change the default LCD: | Following instructions are only given as references or if you want to change the default LCD: | ||
* launch Linux kernel configuration: | * launch Linux kernel configuration: | ||
Revision as of 16:33, 4 March 2011
On this page you will find usefull informations to have a working Linux Framebuffer on your board.
Contents
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, GTK, 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. |
Following instructions are only given as references or if you want to change the default LCD:
- launch Linux kernel configuration:
[armadeus]$ make linux26-menuconfig
- activates:
Device Drivers
---> Character devices --->
[*] Virtual terminal
[*] Support for console on virtual terminal
- on APF9328 activates:
Device Drivers
---> Graphics support
<*> Support for frame buffer devices --->
<*> Motorola i.MX LCD support
- on APF27 activates:
Device Drivers
---> Graphics support
<*> MXC Framebuffer support (Freescale driver)
- and choose your LCD in:
Device Drivers
---> Graphics support
---> LCD Panel (xxxx) --->
- activates:
Device Drivers
---> Graphics support
---> Console display driver support
<*> Framebuffer Console support
- deactivates VGA stuff & add some fonts, then choose Armadeus boot logo:
Device Drivers --->
Graphics support --->
[*] Bootup logo
[*] 224-color Armadeus Linux logo
- recompiles the kernel:
[armadeus]$ make linux26
- now to have console on serial port, you will have to add "console=ttySMX0,115200n8" to your boot parameters
- reflash kernel image on your board and enjoy ! (you should see Linux logo on screen at startup)
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
...
[ ] fbtest
...
---> 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
Tips
- To stop blinking cursor:
# echo 0 > /sys/class/graphics/fbcon/cursor_blink
- To make it blinking again:
# echo 1 > /sys/class/graphics/fbcon/cursor_blink
- To grab a screenshot of a running Framebuffer application, use FBGrab
- 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 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
