brightness control does not work

[Matrix01]

I installed L-14.04 in a while ago.
this brightness control does not work.
any helps?

[varunendra]

What have you tried so far? Looking at your profile above, I assume you must have already searched the forums to find similar issues and their solutions. So... have you tried any of the usual solutions like using boot options or workarounds?

If not, show us the outputs of -

lspci -nnk | grep -iA3 vga
cat /proc/cmdline
for i in /sys/class/backlight/*; do echo -e "\n $i"; cat $i/{brightness,max_brightness,actual_brightness}; done

[Matrix01]

i tried to fix the problem from this;
http://itsfoss.com/fix-brightness-ubuntu-1310/

and
find out my graphic card is Intel.

taro@taro-HP-Mini-110-3000:~$ ls /sys/class/backlight/ acpi_video0 intel_backlight taro@taro-HP-Mini-110-3000:~$ sudo touch /usr/share/X11/xorg.conf.d/20-intel.conf

i do not understand how to the rest.

[Matrix01]

i tried another one from here, and guess brightness is set to maximum to all the time, this is very bright;

http://askubuntu.com/questions/151651/brightness-is-reset-to-maximum-on-every-restart

here's output;

taro@taro-HP-Mini-110-3000:~$ gksudo gedit /etc/rc.local
taro@taro-HP-Mini-110-3000:~$ echo X > /sys/class/backlight/intel_backlight/brightness
bash: /sys/class/backlight/intel_backlight/brightness: Permission denied

[ivan-cuadros-chavez]

Helo

you try to add this video.use_native_backlight=1
in the grub

sudo gedit /etc/default/grub

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash video.use_native_backlight=1"

...and save it. Finally update the grub
sudo update-grub

[varunendra]

First, you did not understand the askubuntu post by mikewhatever correctly. The line "echo X > /sys/class/backlight/intel_backlight/brightness" had to be added to the /etc/rc.local file, not be run in the terminal as a command. And the character 'X' had to be replaced by a number suitable to your card.

Secondly, I think the suggestion by ivan-cuadros-chavez above can be a better approach to 'actually' solve the problem. Please try it first, not the askubuntu post, we'll keep that for later if all other real fixed fail (which they shouldn't, it should be just a matter of finding the correct nerve).

Please let me know if you need step-by-step details of the "video.use_native_backlight=1" fix suggested above. Basically, you have to add this parameter in the /etc/default/grub file, in the line "GRUB_CMDLINE_LINUX_DEFAULT=" as posted above > save > close > run "sudo update-grub" for it to take effect.

[Matrix01]

this did not work.
here is output,
and copy of grub.
Lubuntu has leafpad
256574256575

Helo

you try to add this video.use_native_backlight=1
in the grub

sudo gedit /etc/default/grub

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash video.use_native_backlight=1"

...and save it. Finally update the grub
sudo update-grub

[varunendra]

Please post the outputs of -

cat /proc/cmdline
modinfo video
lsmod
for i in /sys/class/backlight/*; do echo -e "\n $i"; cat $i/{brightness,max_brightness,actual_brightness}; done

While posting the outputs, please use 'Code' tags. It preserves the output's formatting and makes the post cleaner, compact and more readable. To see a quick 'HowTo' with screenshots, please follow the "Use Code Tags" link in my signature.

[Matrix01]

here's output;


taro@taro-HP-Mini-110-3000:~$ cat /proc/cmdline
BOOT_IMAGE=/boot/vmlinuz-3.13.0-35-generic root=UUID=9cd11429-5686-4bb3-b49b-401ca15966f5 ro quiet splash video.use_native_backlight=1 vt.handoff=7
taro@taro-HP-Mini-110-3000:~$ modinfo video
filename: /lib/modules/3.13.0-35-generic/kernel/drivers/acpi/video.ko
license: GPL
description: ACPI Video Driver
author: Bruno Ducrot
srcversion: 3D537E78F15014033076CAC
alias: acpi*:LNXVIDEO:*
depends:
intree: Y
vermagic: 3.13.0-35-generic SMP mod_unload modversions 686
signer: Magrathea: Glacier signing key
sig_key: A2:8D:B5:FD:6E:29:9C:CE:49:47:DA:CA:A6:6F:45:9D:B4 :AC:CE:24
sig_hashalgo: sha512
parm: brightness_switch_enabled:bool
parm: allow_duplicates:bool
parm: use_native_backlight:int
taro@taro-HP-Mini-110-3000:~$ lsmod
Module Size Used by
usb_storage 48417 0
snd_hda_codec_idt 48877 1
snd_hda_intel 42730 1
snd_hda_codec 164067 2 snd_hda_codec_idt,snd_hda_intel
snd_hwdep 13272 1 snd_hda_codec
snd_pcm 85501 2 snd_hda_codec,snd_hda_intel
hp_wmi 13702 0
snd_page_alloc 14230 2 snd_pcm,snd_hda_intel
sparse_keymap 13708 1 hp_wmi
snd_seq_midi 13132 0
snd_seq_midi_event 14475 1 snd_seq_midi
snd_rawmidi 25135 1 snd_seq_midi
bnep 18895 2
rfcomm 53664 0
bluetooth 342208 10 bnep,rfcomm
uvcvideo 71309 0
videobuf2_vmalloc 13048 1 uvcvideo
snd_seq 55383 2 snd_seq_midi_event,snd_seq_midi
videobuf2_memops 13170 1 videobuf2_vmalloc
arc4 12536 2
videobuf2_core 39258 1 uvcvideo
snd_seq_device 14137 3 snd_seq,snd_rawmidi,snd_seq_midi
ath9k 144602 0
coretemp 13195 0
snd_timer 28584 2 snd_pcm,snd_seq
ath9k_common 13359 1 ath9k
ath9k_hw 438205 2 ath9k_common,ath9k
joydev 17101 0
videodev 108503 2 uvcvideo,videobuf2_core
ath 23922 3 ath9k_common,ath9k,ath9k_hw
i915 705659 2
mac80211 546051 1 ath9k
drm_kms_helper 47182 1 i915
serio_raw 13230 0
snd 60939 12 snd_hwdep,snd_timer,snd_hda_codec_idt,snd_pcm,snd_ seq,snd_rawmidi,snd_hda_codec,snd_hda_intel,snd_se q_device,snd_seq_midi
cfg80211 409394 3 ath,ath9k,mac80211
lpc_ich 16864 0
drm 244037 3 i915,drm_kms_helper
soundcore 12600 1 snd
i2c_algo_bit 13197 1 i915
wmi 18673 1 hp_wmi
video 18903 1 i915
parport_pc 31981 0
ppdev 17391 0
mac_hid 13037 0
lp 13299 0
parport 40836 3 lp,ppdev,parport_pc
psmouse 91329 0
ahci 25579 2
r8169 61562 0
libahci 27214 1 ahci
mii 13654 1 r8169
taro@taro-HP-Mini-110-3000:~$ for i in /sys/class/backlight/*; do echo -e "\n $i"; cat $i/{brightness,max_brightness,actual_brightness}; done

/sys/class/backlight/acpi_video0
6
10
6

/sys/class/backlight/intel_backlight
13046
13046
13046
taro@taro-HP-Mini-110-3000:~$

[varunendra]

Please try changing the grub command line option "video.use_native_backlight=1" to "acpi_backlight=vendor" -

sudo sed -i 's/video.use_native_backlight=1/acpi_backlight=vendor/' /etc/default/grub
sudo update-grub

Log off > Re-login > see if brightness control works. If not, try removing the custom xorg file that you created with 'touch' earlier (referenced in post #3 above) -

sudo mv /usr/share/X11/xorg.conf.d/20-intel.conf ./
This will move the file to your home directory. According to your post, it should still be blank. If not, please also post its contents. Do again a log-off > login cycle and see if the brightness control works now.

If the parameter trick doesn't work, we may try the custom xorg file later.

[Matrix01]

fixed,
thank you.

[claracc]

Please, mark as solved.

[varunendra]

Please, mark as solved.

..using "Thread Tools" link above the top post. It'll help many users as brightness problems are common, and all three common alternatives have been mentioned in this thread. Thanks! :)