How to increase brightness on Fujitsu Siemens
Amilo PI22515 notebook with Slackware Linux
A friend of mine has
Fujitsu Siemens Amilo laptop and is
full time using his computer with Slackware Linux.
He is quite happy with
Slackware Linux 13.37 on the laptop,
but unfortunately sometimes his screen brightness lowers. One
example when the screen gets darkened is when he switch the
computer on without being plugged in the electricity grid. This
lowered brightness makes the screen un-user friendly and is quite
tiring for the eye ...
By default the laptop has the usual function keys and in theory
pressing
Function (fn) + F8 / F7 - should increase / decrease
the brightnesswith no problems, however on Slackware Linux (and
probably on other Linuxes too?), the function keys are not properly
recognized and not responding whilst pressed.
I used to have brigtness issues on my Lenovo notebook too and
remember how irritating this was.
After a bit of recalling memories on how I solved this brightness
issues I remembered the screen brigthness on Linux is tunable
through
/proc virtual (memory) filesystem.
The laptop (Amilo) Fujitsu Siemens video card is:
lspci |grep -i vga
00:02.0 VGA compatible controller: Intel Corporation Mobile
GM965/GL960 Integrated Graphics Controller (primary) (rev
03)
I took a quick look in /proc and found few files called
brightness:
- /proc/acpi/video/GFX0/DD01/brightness
- /proc/acpi/video/GFX0/DD02/brightness
- /proc/acpi/video/GFX0/DD03/brightness
- /proc/acpi/video/GFX0/DD04/brightness
- /proc/acpi/video/GFX0/DD05/brightness
cat-ting
/proc/acpi/video/GFX0/DD01/brightness,
/proc/acpi/video/GFX0/DD03/brightness,
/proc/acpi/video/GFX0/DD04/brightness all shows
not
supported and therefore, they cannot be used to modify
brightness:
bash-4.1# for i in
$(/proc/acpi/video/GFX0/DD0{1,3,4,5}/brightness); do \
cat $i;
done
<not supported>
<not supported>
<not supported>
<not supported>
After a bit of testing I finally succeeded in increasing the
brightness.
Increasing the brightness on the notebook
Intel GM965
video card model is done, through file:
/proc/acpi/video/GFX0/DD02/brightness
To see all the brightness levels the Fujitsu LCD display
supports:
bash-4.1# cat /proc/acpi/video/GFX0/DD02/brightness
levels: 13 25 38 50 63 75 88 100
current: 25
As you can see the dark screen was caused cause the
current:
brightness is set to a low value of 25.
To light up the LCD screen and make the screen display fine again,
I
increased the brightness to the maximum level 100,
e.g.:
bash-4.1# echo '100' >
/proc/acpi/video/GFX0/DD02/brigthness
Just for the fun, I've written also a two lines script which
gradually increases LCDs brightness :)
bash-4.1# echo '13' >
/proc/acpi/video/GFX0/DD02/brightness;
bash-4.1# for i in \
$(cat /proc/acpi/video/GFX0/DD02/brightness|grep 'levels'|sed -e
's#levels:##g'); do \
echo $i > /proc/acpi/video/GFX0/DD02/brightness; sleep 1; \
done
fujitsu_siemens_brightness_fun.sh script is fun to observe in
changing the LCD screen gradually in one second intervals :)
Here is also a tiny program that
reduces and increases the notebook laptop brightness written in
C. My friend
Dido, coded it in just few minutes just for
the fun :)
To permanently solve the issues with darkened screen on boot time
it is a good idea to include
echo '100' >
/proc/acpi/video/GFX0/DD02/brigthness in /etc/rc.local:
bash-4.1# echo '100' >
/proc/acpi/video/GFX0/DD02/brigthness
I've also written another Universal Linux Increase brightness Shell
script which should be presumable also working for all Laptop
models running Linux :)
My
maximize_all_linux_laptops_brightness.sh "universal increase Linux
brightness" script is here
I'll be glad to hear from people who had tested the script on other
laptops and can confirm it works fine for them.