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<noinclude>{{ApplicableFor | |||
|MPUs list=STM32MP13x, STM32MP15x | |||
|MPUs checklist=STM32MP13x,STM32MP15x | |||
}}</noinclude> | |||
First identify the backlight device linked to your panel, thanks to the sysfs: | First identify the backlight device linked to your panel, thanks to the sysfs: | ||
{{Board$}} ls /sys/class/backlight | {{Board$}} ls /sys/class/backlight | ||
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{{Board$}} (i=0; while true; do i=$(((i+1)%256)); echo $i > $bl; done) | {{Board$}} (i=0; while true; do i=$(((i+1)%256)); echo $i > $bl; done) | ||
{{Info | Be sure the panel is running (power on) before modifying its backlight.}} | |||
<noinclude> | <noinclude> |
Revision as of 10:02, 8 April 2022
First identify the backlight device linked to your panel, thanks to the sysfs:
ls /sys/class/backlight
5a000000.dsi.0
In the above example, there is a single entry named "5a000000.dsi.0", which is replaced by "*" in the below command.
To adjust the panel backlight, enter the following command:
echo 32 > /sys/class/backlight/*/brightness # set the dsi panel backlight to the value 32
Note: Only values between 0 and max_brightness must be used.
To get the maximum panel backlight value, enter:
cat /sys/class/backlight/*/max_brightness
255
To get the actual panel backlight value, enter:
cat /sys/class/backlight/*/actual_brightness
32
Use one of the following commands to quickly test the panel backlight:
export bl=/sys/class/backlight/5a000000.dsi.0/brightness
# switch on/off test
(while true; do echo 0 > $bl; sleep 0.5; echo 255 > $bl; sleep 0.5; done)
# slow 32-step tests
(i=0; while true; do i=$(((i+32)%256)); echo $i > $bl; sleep 0.5; done)
# fast 1-step test
(i=0; while true; do i=$(((i+1)%256)); echo $i > $bl; done)
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Be sure the panel is running (power on) before modifying its backlight. |