Sony E series brightness control not working in 12.10

**djpeck1** · December 9th, 2012

I have a Sony E series laptop (64 bit) where keys Fn+F5 and Fn+F6 should control the screen brightness. On my machine these keys do control the brightness "slider", but they do not control the actual screen brightness. I am running Ubuntu 12.10. These keys did work to control screen brightness when running Ubuntu 12.04 LTS, but I updated to 12.10 to get EFI boot working correctly.

To date I have tried various kernel bootup options to get the keys working, but none have proved effective. I have tried;
acpi_backlight=video
acpi_backlight=vendor
acpi_osi=Linux
acpi_osi=Linux acpi_backlight=vendor

I had an earlier Sony laptop and to get the brightness controls working on that I had to use a custom gsd_backlight_helper module in gnome-settings-daemon. I've tried that fix for my new Sony, but that also fails to get the brightness controls working.

I'm sure it must be possible to fix this issue, but I'm not sure how to proceed. Can anyone help with this?

**Toz** · December 9th, 2012

Hello and welcome to the forums.

Can you post back the results of the following commands (to identify your backlight interfaces):

Code:

for i in /sys/class/backlight/*; do echo $i; cat $i/brightness; cat $i/max_brightness; done

Can you also run in a terminal window:

Code:

acpi_listen

...press the brightness up and brightness down buttons and post back the codes that are returned.

Maybe we can create some acpi scripts to control the brightness for you.

**djpeck1** · December 9th, 2012

Hi Toz.
Thanks for getting back to me so quickly.
I have run the commands you asked and got the following results;

for i in /sys/class/backlight/*; do echo $i; cat $i/brightness; cat $i/max_brightness; done

/sys/class/backlight/acpi_video0
0
100

acpi_listen

Pressing brightness up gives;

video LCD 00000086 00000000
video PEGP 00000081 00000000
video PEGP 00000081 00000000

Pressing brightness down gives;

video LCD 00000087 00000000
video PEGP 00000081 00000000
video PEGP 00000081 00000000

Please let me know if you need me to run any more commands and thanks again for your assistance with this.

Dave.

**Toz** · December 9th, 2012

Ok, lets make the following changes and see what happens.

Create the following files with the following content (you will need root privileges to do this, so for each file, run "gksu gedit <file>" where <file> is: )

/etc/acpi/events/sony-brightness-up

Code:

event=video LCD 00000086 00000000
action=/etc/acpi/brightup.sh

/etc/acpi/events/sony-brightness-down

Code:

event=video LCD 00000087 00000000
action=/etc/acpi/brightdown.sh

/etc/acpi/brightdown.sh

Code:

#!/bin/bash
curr=`cat /sys/class/backlight/acpi_video0/actual_brightness`
if [ $curr -gt 7 ]; then
   curr=$((curr-8));
   echo $curr  > /sys/class/backlight/acpi_video0/brightness;
fi

/etc/acpi/brightup.sh

Code:

#!/bin/bash
curr=`cat /sys/class/backlight/acpi_video0/actual_brightness`
if [ $curr -lt 93 ]; then
   curr=$((curr+8));
   echo $curr  > /sys/class/backlight/acpi_video0/brightness;
fi

Then, make all 4 of those scripts executable by running the following commands:

Code:

sudo chmod +x /etc/acpi/events/sony-brightness-up
sudo chmod +x /etc/acpi/events/sony-brightness-down
sudo chmod +x /etc/acpi/brightdown.sh
sudo chmod +x /etc/acpi/brightup.sh

And finally, restart acpid:

Code:

sudo service acpid restart

Check if the function keys work now.

**djpeck1** · December 10th, 2012

Hi Toz.
Thanks for your help with this.
I have created and double checked the scripts you specified above (and rechecked that they are executable), but unfortunately they do not allow me to change the screen brightness. The brightness "slider" (top right of the screen) changes when I press the function keys, but the actual screen brightness still does not change. I have even tried rebooting the machine.
Have you any other suggestions that might help? I really appreciate your time with this.
Regards, Dave.

**Toz** · December 10th, 2012

Do these commands change the brightness?

Code:

echo 100 | sudo tee /sys/class/backlight/acpi_video0/brightness
echo 50 | sudo tee /sys/class/backlight/acpi_video0/brightness
echo 0 | sudo tee /sys/class/backlight/acpi_video0/brightness

If not, can you post back:

Code:

cat /proc/cmdline

**chetancr9** · May 26th, 2013

Hi Toz,

I too have the same problem.
Brightness control doesn't work with the function key on sony E series laptop on ubuntu 12.10.
I tried updating in grub but still it didn't work for me.

And here is the output of what u have asked.

chetan@chetan-SVE15115ENB:~$ for i in /sys/class/backlight/*; do echo $i; cat $i/brightness; cat $i/max_brightness; done
/sys/class/backlight/acpi_video0
0
15
chetan@chetan-SVE15115ENB:~$ acpi_listen
sony/hotkey SNC 00000001 00000010
video PEGP 00000081 00000000
sony/hotkey SNC 00000001 0000003b
sony/hotkey SNC 00000001 00000010
video PEGP 00000081 00000000
sony/hotkey SNC 00000001 0000003b
sony/hotkey SNC 00000001 00000010
video PEGP 00000081 00000000
sony/hotkey SNC 00000001 0000003b
sony/hotkey SNC 00000001 00000011
video PEGP 00000081 00000000
sony/hotkey SNC 00000001 0000003b
sony/hotkey SNC 00000001 00000011
sony/hotkey SNC 00000001 0000003b
video PEGP 00000081 00000000
sony/hotkey SNC 00000001 00000011
sony/hotkey SNC 00000001 0000003b
video PEGP 00000081 00000000
sony/hotkey SNC 00000001 00000011
video PEGP 00000081 00000000
sony/hotkey SNC 00000001 0000003b
sony/hotkey SNC 00000001 00000011
video PEGP 00000081 00000000
sony/hotkey SNC 00000001 0000003b
sony/hotkey SNC 00000001 00000011
video PEGP 00000081 00000000
sony/hotkey SNC 00000001 0000003b
sony/hotkey SNC 00000001 00000011
sony/hotkey SNC 00000001 0000003b
video PEGP 00000081 00000000
sony/hotkey SNC 00000001 00000011
video PEGP 00000081 00000000
sony/hotkey SNC 00000001 0000003b
sony/hotkey SNC 00000001 00000011
video PEGP 00000081 00000000
sony/hotkey SNC 00000001 0000003b
sony/hotkey SNC 00000001 00000011
video PEGP 00000081 00000000
sony/hotkey SNC 00000001 0000003b
sony/hotkey SNC 00000001 00000011
video PEGP 00000081 00000000
sony/hotkey SNC 00000001 0000003b
sony/hotkey SNC 00000001 00000011
video PEGP 00000081 00000000
sony/hotkey SNC 00000001 0000003b
sony/hotkey SNC 00000001 00000010
video PEGP 00000081 00000000
sony/hotkey SNC 00000001 0000003b

Kindly help me to control the brightness.

really my eyes are burning with this full brightness

Thanks
Chetan C R

**chetancr9** · May 26th, 2013

Hello All,

I am running Ubuntu 12.10 on Sony E series Laptop

Brightness Control is not working (Fn F5/F6 ) is not working
The brightness remains same for all values (0-15)

I tried to update from the grub it didn't work for me.

Below is the output of commands acpi_listen with brightness + ans - function keys pressed.

chetan@chetan-SVE15115ENB:~$ for i in /sys/class/backlight/*; do echo $i; cat $i/brightness; cat $i/max_brightness; done
/sys/class/backlight/acpi_video0
0
15
chetan@chetan-SVE15115ENB:~$ acpi_listen
sony/hotkey SNC 00000001 00000010
video PEGP 00000081 00000000
sony/hotkey SNC 00000001 0000003b
sony/hotkey SNC 00000001 00000010
video PEGP 00000081 00000000
sony/hotkey SNC 00000001 0000003b
sony/hotkey SNC 00000001 00000010
video PEGP 00000081 00000000
sony/hotkey SNC 00000001 0000003b
sony/hotkey SNC 00000001 00000011
video PEGP 00000081 00000000
sony/hotkey SNC 00000001 0000003b
sony/hotkey SNC 00000001 00000011
sony/hotkey SNC 00000001 0000003b
video PEGP 00000081 00000000
sony/hotkey SNC 00000001 00000011
sony/hotkey SNC 00000001 0000003b
video PEGP 00000081 00000000
sony/hotkey SNC 00000001 00000011
video PEGP 00000081 00000000
sony/hotkey SNC 00000001 0000003b
sony/hotkey SNC 00000001 00000011
video PEGP 00000081 00000000
sony/hotkey SNC 00000001 0000003b
sony/hotkey SNC 00000001 00000011
video PEGP 00000081 00000000
sonyl/hotkey SNC 00000001 0000003b
sony/hotkey SNC 00000001 00000011
sony/hotkey SNC 00000001 0000003b
video PEGP 00000081 00000000
sony/hotkey SNC 00000001 00000011
video PEGP 00000081 00000000
sony/hotkey SNC 00000001 0000003b
sony/hotkey SNC 00000001 00000011

Kindly help me to solve this problems

**mörgæs** · May 26th, 2013

Threads merged.
Please don't post multiple threads on the same subject.

**Toz** · May 26th, 2013

@chetancr9, does your Sony model come with an AMD video card?

Code:

sudo lspci -vnn | grep -A15 VGA

...If so, have you installed the proprietary drivers?

Does the following command change the brightness?

Code:

echo 7 | sudo tee /sys/class/backlight/acpi_video0/brightness

What kernel boot kernel parameters are you using?

Code:

cat /proc/cmdline

...have you tried the acpi_backlight=vendor parameter?

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