Problems with backlight

Zuba · 2011-04-15 20:48:35

Hi. I have Samsung N150 Plus. I've installed samsung-tools to manage backlight. But, i wan't the backlight to turn off after 5 minutes. I've tried setting dpms, with "xset dpms 600 600 600", and after 5 minutes it goes off, but after 2 seconds it goes on again, and the backlight is blinking. How can i fix that? I think this have something to do with samsung-tools, but i need it to even change the backlight.

jeslinmx · 2011-04-16 00:43:01

Can your backlight support changing over /sys?

Zuba · 2011-04-16 11:30:22

I don't know. How can i check it?

jeslinmx · 2011-04-16 13:24:25

For me, it is under /sys/class/backlight/acpi_video0. Try cd /sys and find | grep backlight

Zuba · 2011-04-16 13:37:22

There are some entries there, but i think they're there because of samsung-tools.

ewaller · 2011-04-16 14:49:06

Zuba wrote:

There are some entries there, but i think they're there because of samsung-tools.

Specifically, is there a file called 'brightness' in that tree? Also is there a file called 'max_brightness' in that tree?

ewaller@odin:/sys 1017 %find | grep backlight | grep brightness
./devices/virtual/backlight/acpi_video0/brightness
./devices/virtual/backlight/acpi_video0/actual_brightness
./devices/virtual/backlight/acpi_video0/max_brightness
ewaller@odin:/sys 1018 %cat ./devices/virtual/backlight/acpi_video0/max_brightness
10
ewaller@odin:/sys 1019 %cat ./devices/virtual/backlight/acpi_video0/brightness 
10
ewaller@odin:/sys 1020 %sudo bash -c "echo 5 > ./devices/virtual/backlight/acpi_video0/brightness"
Password: 
ewaller@odin:/sys 1021 %

sets my display brightness to 50%

Zuba · 2011-04-16 14:53:34

But the thread is not about that i can't control brightness at all, it's just that it won't turn off after a period of time (it just starts blinking).

ewaller · 2011-04-16 15:09:18

Zuba wrote:

But the thread is not about that i can't control brightness at all, it's just that it won't turn off after a period of time (it just starts blinking).

I really need to get more sleep

What environment are you using? (KDE, Awesome, *box, Gnome, tty, etc...)

Zuba · 2011-04-16 15:17:03

Gnome.

jeslinmx · 2011-04-17 00:19:23

Have you tried gnome power management? You probably would have but just making sure.
A quick and dirty fix would be to schedule a script which echoes a value into your sys backlight file.

Zuba · 2011-04-17 10:38:06

Same as with dpms, but it's not blinking. It just turns off for 2 seconds, then it turns back on again.

ctxfi-user · 2011-04-17 12:22:37

I have the same problem on a Samsung N140. If I remember correctly it worked flawless until Kernel 2.6.36 and I never used the samsung-tools. Since then also the steps for adjusting the brightness became bigger. Maybe the problem is related to that. I noticed, that it is also possible to get the blinking thing when you adjust the brightness manually.

Zuba · 2011-04-17 13:02:49

Yea, that's right. Sometimes even the computer hangs up when i'm trying to change brightness, i need to reboot manually.

Arch Linux

#1 2011-04-15 20:48:35

Problems with backlight

#2 2011-04-16 00:43:01

Re: Problems with backlight

#3 2011-04-16 11:30:22

Re: Problems with backlight

#4 2011-04-16 13:24:25

Re: Problems with backlight

#5 2011-04-16 13:37:22

Re: Problems with backlight

#6 2011-04-16 14:49:06

Re: Problems with backlight

#7 2011-04-16 14:53:34

Re: Problems with backlight

#8 2011-04-16 15:09:18

Re: Problems with backlight

#9 2011-04-16 15:17:03

Re: Problems with backlight

#10 2011-04-17 00:19:23

Re: Problems with backlight

#11 2011-04-17 10:38:06

Re: Problems with backlight

#12 2011-04-17 12:22:37

Re: Problems with backlight

#13 2011-04-17 13:02:49

Re: Problems with backlight

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