“How to modify the panel backlight”的版本间的差异

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[[Category:Linux_Operating_System]]
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First identify the backlight device linked to your panel, thanks to the sysfs:
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[[Category:Visual]]
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{{Board$}} ls /sys/class/backlight
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[[Category:DRM_KMS]]
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5a000000.dsi.0
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In the above example, there is a single entry named "5a000000.dsi.0", which is '''replaced by "*"''' in the below command.
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To adjust the panel backlight, enter the following command:
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{{Board$}} echo '''32''' > /sys/class/backlight/*/'''brightness'''    # set the dsi panel backlight to the value '''32'''
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Note: Only values between 0 and '''max_brightness''' must be used.
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To get the maximum panel backlight value, enter:
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{{Board$}} cat /sys/class/backlight/*/'''max_brightness'''
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255
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To get the actual panel backlight value, enter:
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{{Board$}} cat /sys/class/backlight/*/'''actual_brightness'''
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32
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Use one of the following commands to quickly test the panel backlight:
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{{Board$}} export bl=/sys/class/backlight/5a000000.dsi.0/brightness
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{{Board$}} # switch on/off test
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{{Board$}} (while true; do echo 0 > $bl; sleep 0.5; echo 255 > $bl; sleep 0.5; done)
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{{Board$}} # slow 32-step tests
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{{Board$}} (i=0; while true; do i=$(((i+32)%256)); echo $i > $bl; sleep 0.5; done)
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{{Board$}} # fast 1-step test
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{{Board$}} (i=0; while true; do i=$(((i+1)%256)); echo $i > $bl; done)
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<noinclude>
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{{PublicationRequestId | 10715 | 2019-02-18 | AnneJ}}
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[[Category:How to run use cases]]
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[[Category:DRM KMS]]
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</noinclude>

2020年5月8日 (五) 22:31的最新版本

First identify the backlight device linked to your panel, thanks to the sysfs: 

Board $> 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: 

Board $> 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: 

Board $> cat /sys/class/backlight/*/max_brightness
255

To get the actual panel backlight value, enter: 

Board $> cat /sys/class/backlight/*/actual_brightness
32


Use one of the following commands to quickly test the panel backlight: 

Board $> export bl=/sys/class/backlight/5a000000.dsi.0/brightness

Board $> # switch on/off test
Board $> (while true; do echo 0 > $bl; sleep 0.5; echo 255 > $bl; sleep 0.5; done)

Board $> # slow 32-step tests
Board $> (i=0; while true; do i=$(((i+32)%256)); echo $i > $bl; sleep 0.5; done)

Board $> # fast 1-step test
Board $> (i=0; while true; do i=$(((i+1)%256)); echo $i > $bl; done)


<securetransclude src="ProtectedTemplate:PublicationRequestId" params="10715 | 2019-02-18 | AnneJ"></securetransclude>

取自“http://wiki.100ask.org/index.php?title=How_to_modify_the_panel_backlight&oldid=6845”