Ubuntu – How to increase the screen brightness control sensitivity

13.04brightnessscreen

In Ubuntu 13.04, when I use the keyboard hotkeys to control my screen brightness, I only get 5 steps to go from the darkest to the brightest level, for a total of 6 levels.

However, I noticed a really strange behavior. If I click in any indicator, for example, in the clock so the calendar is displayed, while the menu (in this example, the calendar) is being displayed, I get 15 steps to go from the darkest to the brightest level, for a total of 16 levels, but I don't get the on-screen brightness notification though. This also occurs when the screen is locked. Maybe you, dear reader, haven't noticed this behavior so please try it.

This shows that somehow Ubuntu knows how to make use of the full brightness sensitivity, but it fails to do so under "normal" conditions (e.g. while a indicator menu is not being displayed, or the screen is not locked).

It also seems that the thing responsible for the on-screen brightness notification is doubling or tripling the brightness change on every step.

Having only 6 levels of brightness is very problematic because you can't adjust correctly the brightness according to the changing lighting conditions of your environment. In Windows in the same laptop, I get 16 levels of brightness as well.

How can I improve/increase the screen brightness sensitivity permanently?

Perhaps disabling the on-screen brightness notification? I could live without it if I get the brightness sensitivity back.

Best Answer

I have also noticed this issue on my Hp dv6t-7000 laptop with Intel HD 3000 graphics and a Nvidia GT 630m Optimus card. I eventually found a fix that worked from the Arch Linux wiki.

Basically my situation was that acpi_video0 was controlling the back-light, acpi_video0 is for ATI graphics. So, I added the following to the grub command line in /etc/default/grub acpi_osi="!Windows2012" acpi_backlight=vendor, so now it looks like this:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash i915.semaphores=1 acpi_osi="!Windows2012"  acpi_backlight=vendor"

Then ran:

sudo update-grub2

A reboot and the sensitivity is fixed.

Hope this helps.

Related Solutions

Ubuntu – Why does Ubuntu reset brightness settings at the loading screen

With this guide you can save your brightness level on reboot/shutdown and bring it back after system startup. This does not affect system boot up time.

Make a text file in your home directory (or wherever else) to save the brightness level in it. Open up terminal by pressing Ctrl+Alt+T, then enter the following command:

sudo gedit /home/brightness

Save and exit gedit. Just let it be empty. Then type this command in terminal:

sudo gedit /etc/rc0.d/K99FixBrightness

And copy paste the following bash script into it:

#!/bin/bash
brightness=`cat /sys/class/backlight/acpi_video0/brightness`
echo $brightness > /home/brightness
exit 0

Then make it executable by entering: sudo chmod 644 /etc/rc0.d/K99FixBrightness in terminal. Rpeat above steps with rc6.d directory:

sudo gedit /etc/rc6.d/K99FixBrightness

Just so:

#!/bin/bash
brightness=`cat /sys/class/backlight/acpi_video0/brightness`
echo $brightness > /home/brightness
exit 0

Then make it executable by entering: sudo chmod 644 /etc/rc6.d/K99FixBrightness in terminal. Until now we set up the brightness level to be saved in /home/brightness before shutdown and reboot. One step to go! Enter the following command in terminal:

sudo gedit /etc/rc.local

Add this before the last line "exit 0":

brightness=`cat /home/brightness`
echo $brightness > /sys/class/backlight/acpi_video0/brightness

Save and exit gedit. Now with system startup the last brightness level will be loaded!

Done! :)

Ubuntu – Set the screen brightness on startup

You cannot call xbacklight in rc.local, because rc.local is not running in the X environment.

Add this command to your startup programs (gnome-session-properties):

xbacklight -set 50%

This will work

Best Answer

Related Solutions

Ubuntu – Why does Ubuntu reset brightness settings at the loading screen

Done! :)

Ubuntu – Set the screen brightness on startup

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