Changing brightness at startup

Question

My Lenovo T440s starts up with maximum brightness. Following this thread I have tried to alter rc.local, but this does not work.

When I execute the command cat /sys/class/backlight/acpi_video0/brightness I get the output 851. Then I lower my brightness manually via the hotkeys and execute the command again - it still shows 851.

This leads me to believe that I cannot control my brightness in this way by simply adding a command to rc.local.

Is there anything else I can try?

---

Here is the grub content

# If you change this file, run 'update-grub' afterwards to update
# /boot/grub/grub.cfg.
# For full documentation of the options in this file, see:
#   info -f grub -n 'Simple configuration'

GRUB_DEFAULT="0"
GRUB_HIDDEN_TIMEOUT="0"
GRUB_HIDDEN_TIMEOUT_QUIET="true"
GRUB_TIMEOUT="2"
GRUB_DISTRIBUTOR="`lsb_release -i -s 2> /dev/null || echo Debian`"
#GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"
GRUB_CMDLINE_LINUX=""

# Uncomment to enable BadRAM filtering, modify to suit your needs
# This works with Linux (no patch required) and with any kernel that obtains
# the memory map information from GRUB (GNU Mach, kernel of FreeBSD ...)
#GRUB_BADRAM="0x01234567,0xfefefefe,0x89abcdef,0xefefefef"

# Uncomment to disable graphical terminal (grub-pc only)
#GRUB_TERMINAL="console"

# The resolution used on graphical terminal
# note that you can use only modes which your graphic card supports via VBE
# you can see them in real GRUB with the command `vbeinfo'
#GRUB_GFXMODE="640x480"

# Uncomment if you don't want GRUB to pass "root=UUID=xxx" parameter to Linux
#GRUB_DISABLE_LINUX_UUID="true"

# Uncomment to disable generation of recovery mode menu entries
#GRUB_DISABLE_RECOVERY="true"

# Uncomment to get a beep at grub start
#GRUB_INIT_TUNE="480 440 1"

GRUB_DISABLE_OS_PROBER="true"

---

Here is the rc.local content

#!/bin/sh -e
#
# rc.local
#
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits.
#
# By default this script does nothing.

#echo 2 > /sys/class/backlight/acpi_video0/brightness
#echo 2 > /sys/class/backlight/intel_backlight/brightness

#xrandr --output eDP1 --brightness 0.3
rfkill block bluetooth
#echo 3 > /sys/class/backlight/thinkpad_screen/brightness
exit 0

Answer 1

Have you tried using some software to avoid manually dealing with the sys filesystem? I suggest using xbacklight.

xbacklight -set 10

This command will set the brightness of the screen to 10%. You can add that to your rc.local.

Edit: If the above procedure is not working there might be some problems between the kernel and the bios acpi. Edit the file: /boot/grub/menu.lst

Add the following parameters to the default configuration: thinkpad-acpi.brightness_enable=1 acpi_backlight=vendor

The default line shoud look something like this:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash thinkpad-acpi.brightness_enable=1 acpi_backlight=vendor"

Save the modified file and run:

sudo update-grub

Reboot and check if xbacklight is working

Answer 2

This is obviously a Kernel Compatibility issue with some Hardwares, and I just want you to try this workaround:

1. Backup and open grub file. Open terminal ( Ctrl+Alt+T ) and type:

   sudo cp /etc/default/grub /etc/default/grub.bak
   sudo gedit /etc/default/grub
   

2. You will find this line in the new opened window: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

   Change it to:

   GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"
   

3. Save and close the window and update your grub:

   sudo update-grub
   

4. Restart your system:

   sudo reboot
   

if above procedure doesn't work then repeat the same step but this time try to change the line in step 2 with this:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash pcie_aspm=force"

Reply if something goes wrong. If it doesn't work, please edit your question and paste you grub file contents: cat /etc/default/grub

Answer 3

If you are using Gnome 3 or Unity -

Checkout the master branch from https://github.com/ishanthilina/setBrightness.

If you are using Gnome 2 -

Checkout the Gnome2 branch from https://github.com/ishanthilina/setBrightness.

This is a python script solve your problem.

The command to be given in the startup applications is “python ////setBrightness.py < Brightness level>”.

An example would be python /home/ishan/.setBrightness/setBrightness.py 20 . If you do not specify a brightness level, the script will change the brightness level according to the time of the day. If it’s between 7am and 8pm, the script will make the brightness be set to 75.

If it’s between 8pm and 7am, the script will make the brightness be set to 20. You can edit these brightness levels by changing the variables day_level and night_level respectively.

source

Answer 4

From the wording of your question I think you only tried controlling the brightness with /sys/class/backlight/acpi_video0/brightness, but there are possibly other brightness controlling pseudo-files in your /sys/ file system. See my answer here, which I sum up below:

1. Run

   tail /sys/class/backlight/*/brightness
   

   will output something like

   ==> /sys/class/backlight/acpi_video0/brightness <==
   7
   
   ==> /sys/class/backlight/radeon_bl/brightness <==
   255
   
   ==> /sys/class/backlight/toshiba/brightness <==
   -5
   

2. Now lower or increase the brightness level as you normally do, and after that run again: tail /sys/class/backlight/*/brightness , will output the new values, e.g.:

   ==> /sys/class/backlight/acpi_video0/brightness <==
   6
   
   ==> /sys/class/backlight/radeon_bl/brightness <==
   255
   
   ==> /sys/class/backlight/toshiba/brightness <==
   -5
   

3. The file for which the outputed number in the above output is changed after adjusting the brightness is the file which controls your brightness, so you will have to use that one.

Answer 5

Then I lower my brightness manually via the hotkeys and execute the command again ...

As you can lower the brightness using Hokeys the following dbus or xdotool method should work

xbacklight

$ xbacklight +30% # increases brightness by 30 percent
$ xbacklight -30% # decreases brightness by 30 percent

dbus way

$ dbus-send --session --print-reply \
      --dest="org.gnome.SettingsDaemon" \
      /org/gnome/SettingsDaemon/Power \
      org.gnome.SettingsDaemon.Power.Screen.SetPercentage \
      uint32:<percentage>

Example

Set brightness to 30%:

$ dbus-send --session --print-reply \
      --dest="org.gnome.SettingsDaemon" \
      /org/gnome/SettingsDaemon/Power \
      org.gnome.SettingsDaemon.Power.Screen.SetPercentage \
      uint32:30 

Or
To decrease brightness by a step (~7)

$ dbus-send --session --print-reply \
      --dest="org.gnome.SettingsDaemon" \
      /org/gnome/SettingsDaemon/Power \
      org.gnome.SettingsDaemon.Power.Screen.StepDown

To increase brightness by a step (~7)

$ dbus-send --session --print-reply \
      --dest="org.gnome.SettingsDaemon" \
      /org/gnome/SettingsDaemon/Power \
      org.gnome.SettingsDaemon.Power.Screen.StepUp

If it says as follows your OS may be too old. Then use xdotool:

Error org.freedesktop.DBus.Error.UnknownMethod: 
Method "SetPercentage" with signature "u" on interface 
"org.gnome.SettingsDaemon.Power.Screen" doesn't exist

xdotool

• Increase brightness:

  $ xdotool key XF86MonBrightnessUp
  

• Decrease brightness:

  $ xdotool key XF86MonBrightnessDown
  

After successfully tested ant of above method you can add it to /etc/rc.local

Software way
If you cant's use any of the following method to adjust your hardware back-lid brightness then adjust the software brightness of your display.
xrandr --output OUTPUT --brightness VALUE
For exapmle
xrandr --output LVDS1 --brightness 0.9
You can find connected displays using xrandr | grep connected

Answer 6

I had a similar problem on my t430s after I upgraded from OpenSuse 12.3 (3.7 kernel) to 13.1 (3.11 kernel). The display was always at max brightness on boot, but my bigger concern was that the brightness function keys were (usually) not working. Xbacklight would (usually) work, but not always. If I'd change the brightness to 80 using xbacklight, that would work. If I'd change it to 70, nothing would happen until I pressed the reduce-brightness function key. Then it would drop to (about?) 70%. It was really weird.

For unrelated reasons, I switched to Mint 16 Cinnamon before I found a solution. The function keys are working fine now, so I haven't looked into it further. (I'm NOT suggesting switching distros as a solution, BTW!) Before I switched, here's what I learned:

I read (somewhere??) that the 3.8 + kernels address a hardware trend related to Windows 8: Win8 requires hardware to report back 101 brightness levels; the t430 only supports 16. I'm guessing that the kernel is "asking" hardware that "thinks" in 1/16ths for a brightness change of 1/101th! (Please don't quote me on this.)

Instead of using acpi_backlight=vendor in /etc/default/grub, you could try acpi_backlight="!Windows 2012" -- i.e., tell it "I'm not using Windows 8!" Some of the OpenSuse folks were having success with this, though none of them were using Thinkpads. Give it a shot.