Broken backlight brightness control

Is there a way to address this issue in Archlinux?
Brightness control keys were not working in GNOME, even with the kernel boot parameter acpi_backlight=vendor.

heimer16 wrote:
I had the same issue here.
I saw a brief mention in the arch wiki: https://wiki.archlinux.org/index.php/Backlight
that says the kernel parameter: video.use_native_backlight=1 is now default in 3.16,
so I added video.use_native_backlight=0 to my kernel parameters and my backlight functionality is back.
awesome thx, worked for me as well. I used the -u option of efibootmgr
efibootmgr -c -d /dev/sda -p 1 -L Gentoo3.16.3-rev1 -l "\efi\boot\kernel_3.16.3-rev1.efi" -u "video.use_native_backlight=0"

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[SOLVED] Broken backlight brightness adjustment on x220 after recent-

Hi.
I'm no longer able to adjust backlight brightness with hotkeys and xbacklight.
I believe issue appeared after update to linux-3.16.
Brightness adjustment keys are detected correctly in xev.
Echoing brightness value to /sys/class/backlight/intel_backlight/brightness does adjust brightness.
But xbacklight and hotkeys won't do a thing.
I already tried some magic I don't understand: acpi_backlight=vendor and acpi_osi=linux. No luck here.
Anyone else with the same issue? Are there any fixes for this?
Thanks in advance.
Solution (thanks, heimer16):
https://bbs.archlinux.org/viewtopic.php … 3#p1448253
Last edited by eDio (2014-08-18 23:27:52)

heimer16 wrote:
I had the same issue here.
I saw a brief mention in the arch wiki: https://wiki.archlinux.org/index.php/Backlight
that says the kernel parameter: video.use_native_backlight=1 is now default in 3.16,
so I added video.use_native_backlight=0 to my kernel parameters and my backlight functionality is back.
awesome thx, worked for me as well. I used the -u option of efibootmgr
efibootmgr -c -d /dev/sda -p 1 -L Gentoo3.16.3-rev1 -l "\efi\boot\kernel_3.16.3-rev1.efi" -u "video.use_native_backlight=0"

Reverse screen or backlight brightness control

So is anyone aware of a way to reduce brightness or reverse the ecreen of Ipod Video, so that it does not burn your retina out in the dark? I spend way to much time on flights, often at night when they turn off the cabin lights. Like many other travellers, my ipod is the one thing keeping me sane during hose long haul trips. But in the dark cabin, the screen is so bright it wakes half the cabin up and renders me night blind for 5 minutes! And is probably responsible for increased UFO sightings (think about it).
If not, I guess I will be buying the iShades accessory which will no doubt be launched April 1st?
Dell XPS600 Windows XP Pro The Apple Newton was ahead of its time, bring it back now!

Well no there is no way to reduce the backlight brightness. And also we are not allowed to talk abou Apple's unanounced products and I doubt they will release shades.

Mysterious forces changing backlight brightness

Some mysterious forces are changing my laptop's brightness and I can't seem to figure it out what it is.
For example, if my battery gets below 10% (also, why 10%?), it automatically changes brightness to something very low.
Similarly, if battery gets fully charged, it changes brightness. It also happens when I plug it into the AC or remove the adapter.
I've looked everywhere, tried changing settings (I really don't remember which ones anymore), but nothing seems to work.
Also, I've xfce4-power-manager installed, but closing it doesn't seem to effect this backlight changing.
Laptop-mode-tools is also set up, but backlight control is disabled.
My only idea is that it's changed by the driver, but how can I control it?
edit:
[soz@arch ~]$ lspci | grep VGA
00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09)
Also, changing backlight to vendor doesn't fix this. Instead it messes up xfce4-power-manager's backlight control.
Forgot to mention, I'm running a simple Openbox installation.
Last edited by socials (2013-11-15 20:47:44)

Alright, an update.
The same thing happens even without running X at all. Even the brightness control keyboard hotkeys work without an X server running.
So it seems that they interact directly with hardware and it's not related to software at all. I think it's safe to say that the brightness change events happening on charger plug/unplug are related to this as well.
So if there's nothing in BIOS (I checked) I guess it's not fixable. I could set up an dirty hack using acpi handler scripts although it seems like an awful solution.
Or have you guys any other ideas?

Satellite C650-I5011 - Brightness control is not working

Hi,
I have a Toshiba C650 - I5011 model with Ubuntu 10.3 . I have a problem that even after pressing the Fn + F6 key, the brightness of my LCD does'nt change.
It remains at maximum.
I have installed both Toshutils and hotkey daemon. My volume control key (on numeric alternate) works perfectly fine but none of the Function keys work. Pls help.
Also, I had errors during installation of Ubuntu on my laptop because of which I had to permanently disable ACPI, else it won't boot. Following is the lspci output :
00:00.0 Host bridge: Intel Corporation Core Processor DRAM Controller (rev 02)
00:02.0 VGA compatible controller: Intel Corporation Core Processor Integrated Graphics Controller (rev 02)
00:16.0 Communication controller: Intel Corporation 5 Series/3400 Series Chipset HECI Controller (rev 06)
00:1a.0 USB Controller: Intel Corporation 5 Series/3400 Series Chipset USB2 Enhanced Host Controller (rev 05)
00:1b.0 Audio device: Intel Corporation 5 Series/3400 Series Chipset High Definition Audio (rev 05)
00:1c.0 PCI bridge: Intel Corporation 5 Series/3400 Series Chipset PCI Express Root Port 1 (rev 05)
00:1c.1 PCI bridge: Intel Corporation 5 Series/3400 Series Chipset PCI Express Root Port 2 (rev 05)
00:1c.4 PCI bridge: Intel Corporation 5 Series/3400 Series Chipset PCI Express Root Port 5 (rev 05)
00:1d.0 USB Controller: Intel Corporation 5 Series/3400 Series Chipset USB2 Enhanced Host Controller (rev 05)
00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev a5)
00:1f.0 ISA bridge: Intel Corporation Mobile 5 Series Chipset LPC Interface Controller (rev 05)
00:1f.2 SATA controller: Intel Corporation 5 Series/3400 Series Chipset 4 port SATA AHCI Controller (rev 05)
00:1f.3 SMBus: Intel Corporation 5 Series/3400 Series Chipset SMBus Controller (rev 05)
00:1f.6 Signal processing controller: Intel Corporation 5 Series/3400 Series Chipset Thermal Subsystem (rev 05)
01:00.0 Ethernet controller: Atheros Communications AR8152 v1.1 Fast Ethernet (rev c1)
02:00.0 Network controller: Atheros Communications Inc. AR9285 Wireless Network Adapter (PCI-Express) (rev 01)

Hello,
The backlight detection depends from acpi options selection on your kernel. Which kernel version do you use ?
$ uname -a
(Use at least a 2.6.36 kernel since a lot of improvement for recent Toshiba laptop have been done during summer 2010)
This done, ACPI options beeing compiled into kernel or loaded as module, this line should appear in your /var/log/Xorg.0.log :
"found backlight control interface /sys/class/backlight/acpi_video0"
Having a C650-15Z, my brightness control works well.
regards,
alex

Windows 8.1 update and brightness control

I have a DELL XPS L521X with Windows 8.1 (I had windows 8 some days ago) and I have had two problems:
1) I did not allow Windows to upgrade to 8.1 and it forced me to do it. It gave me 15 minutes to save progress and do it. I was watching the NBA finals on my computer and it was the only thing I had to watch the game. The installation lasted the whole second
half the game and I WAS NOT ABLE TO WATCH IT DUE TO THIS, YOU CAN IMAGINE HOW I AM FEELING ABOUT NOT USING WINDOWS EVER AGAIN... How can I prevent it from ever upgrading anything without my consent? I had already turned off updates from Control Panel\System
and Security\Windows Update but it didn't help.
2) My brightness control became broken after the 8.1 update. I had to manually pick the older Intel HD 4000 driver to have it working again or else my eyes would stop functioning after such a bright display. I had to switch to the 9.17 driver version from
September 2012. Where can I get the lastest WORKING version of the driver?
Please stop making me loose days fixing Windows issues...

Hi,
We have set the GP to disable Windows 8.1 update in Windows store, you can check it here:
How to Disable “Update to Windows 8.1 for Free” Notification in Windows 8 Store?
http://www.askvg.com/how-to-disable-update-to-windows-8-1-for-free-notification-in-windows-8-store/
For your second issue, it's not only related to Windows, but also the driver provider. Microsoft is working together with the device manufacturers and partners to deliver update package and try the best to solve the compatible issue and bring a great improvement
on user experience. But you know, it will take some time.
Thanks for your understanding.
Kate Li
TechNet Community Support

Any ideas on why 4s brightness control won't work (not auto brightness)

Within the past week or so my brightness control stopped working. Restored OS but that didn't fix it. I suppose it is just broken but seems an unlikely failure when everthing else still works.
I've read all the threads on the auto brightness issues and fixes, but this is not that. The brightness slider does nothing with or without auto control on and in a dark room or full daylight.
Anything else I might try short of replace the phone?
Not a huge issue except for the fact that the already short battery life is reduced by no longer being able to reduce the brightness.

If this is just happening on your home wifi, you might want to try unplugging your router for 15 seconds, then pluggint it back in. Then on your devices, go to Settings>General>Reset and tap Reset Network Settings. Note: this will erase passwords for previously joined networks so you'll have to rejoin your wifi again.

Brightness control at startup with systemd

I finally upgraded to systemd (I know... a bit later than I should have), and the transistion has been smooth, except for enabling brightness controll at boot.
I currently have a bit of a hack working to enable brightness control on my Dell XPS 13 ultrabook. I have two backlight interfaces (/sys/class/backlight/intel_backlight and /sys/class/backlight/acpi_video0), and I have found that the only way to alter my screen brightness is to set the intel_backlight brightness value to 0 and then alter the brightness file under the acpi_video0 interface. I must always write the 0 to the intel_backlight/brightness file, even if it already contains 0, to enable brightness control through acpi_video0.
I had had this code in my rc.local previously, and it worked exactly as I needed to enable brightness control:
#!/bin/bash
# set intel interface to 0, allowing acpi interface to take precedence
echo 0 > /sys/class/backlight/intel_backlight/brightness
# set the permissions of the acpi brightness file for video group (me) regular user modification
chgrp video /sys/class/backlight/acpi_video0/brightness
chmod 664 /sys/class/backlight/acpi_video0/brightness
# initialize brightness to a low level
echo 3 > /sys/class/backlight/acpi_video0/brightness
exit 0
Currently when I run this script normally it grants me the brightness control I desire through the modification of /sys/class/backlight/acpi_video0/brightness. I have made this script into a systemd service initiated at startup, with the service file below:
[Unit]
Description=Brightness Control Initialization
[Service]
Type=oneshot
ExecStart=/usr/lib/systemd/scripts/bright_init
RemainAfterExit=yes
[Install]
WantedBy=multi-user.target
My issue is that although the service is initiated at startup without error, my brightness control does not function like it does when I run the script manually myself. I have verified that systemd considers the service to have run successfully after startup, and I have also enabled both the multi-user.target and above service.
My questions are twofold:
1. Is there a better way to allow brightness control other than the somewhat hacky method of zeroing the /sys/class/backlight/intel_backlight/brightness file with the above script?
2. And does anyone have an idea as to why my service doesn't work, even though I can run the script after startup and it functions as I desire?
Last edited by tyler.heck (2012-11-16 01:45:46)

It is interesting to see that this is working for you. I had to add OWNER="root" to the rule. Otherwise when testing the rule with `udevadm test` I always recieved a permission denied error. But even with OWNER="root" Udev did not actually write the ATTR{brightness}="2" into the file.
Manually doing that by echo 2 > ... works well. I searched a bit on this topic and found a thread on the Gentoo forum where they say that it is not wise to use Udev for writing anything to /sys. Instead you should use Udev to run a script that does that:
[orschiro@thinkpad ~]$ cat /etc/udev/rules.d/50-powersave.rules
SUBSYSTEM=="power_supply", ENV{POWER_SUPPLY_ONLINE}=="0", RUN+="/home/orschiro/Scripts/powersaving battery"
SUBSYSTEM=="power_supply", ENV{POWER_SUPPLY_ONLINE}=="1", RUN+="/home/orschiro/Scripts/powersaving AC"
[orschiro@thinkpad ~]$ cat /usr/local/bin/powersaving
#!/bin/sh
case $1 in
battery)
echo "Running powersaving on AC in 3 seconds"
sleep 3
# screen power saving"
echo 200000 > /sys/class/backlight/intel_backlight/brightness
AC)
echo "Running powersaving on battery in 3 seconds"
sleep 3
# screen power saving
echo 4270725 > /sys/class/backlight/intel_backlight/brightness
esac
Last edited by orschiro (2013-03-01 15:29:02)

Brightness control from Apple keyboard

I have a LG 23'' Flatron W2361V and I can not control the brightness from the keyboard. Is this normal for a none Apple display or am I missing something? This is my first Mac Pro and I have only used Macbook Pro's and iMac's which have screens of course. The volume key works and other keys as well. Need help.

Apple displays allow control of the backlight brightness via USB. Non-Apple displays don't, so there is no way for the computer to change the backlight brightness. There is software to reduce brightness by changing the output from the computer, but this will reduce the number of brightness and color steps available, and since the backlight brightness is unchanged, will use more power.
<http://www.charcoaldesign.co.uk/shades>

Application brightness control

Hi everyone,
main problem is that in Trine2 game, brightness control does nothing to the screen. So with default brightness, that's set in game, whole screen is very dark.
It's desktop computer with proprietary nvidia driver (graphic card is GTX 660). System is fully updated, so versions of all my packages are latest available. Additionally I've put option in xorg.conf that's documented in wiki, but it doesn't help. Maybe to mention that brightness control in nvidia-settings GUI is working.
Can someone point me to direction where to look for solution? Or is there some command/app that could set brihtness/gama for particular application?

try this in your shell terminal
for i in /sys/class/backlight/*; do cat $i/max_brightness > $i/brightness; done

Software Brightness Controls Not Working (Dell D630)

I've just encountered a problem with my software brightness controls on a fresh install of Archlinux (using KDE as the desktop environment). I can adjust my display's brightness to my heart's content using the brightness keys on my keyboard, but none of the stuff in KDE power management works. In addition, I've also tried the xbacklight program without success. It doesn't give me any errors, it just fails to adjust the backlight at all. Any ideas why this is happening and what I might be able to do to fix it?
Thanks!

Moving to Laptop issues...
There are quite a few threads about backlight issues with the 3.13.x. kernels.

Problem with brightness control on Toshiba Satellite R830 [SOLVED]

Ever since I've been using Linux on my Toshiba Satellite R830 laptop I had problems with the brightness setting after wakeup from sleep. The solution I had found was to use a custom xorg.conf setup. Actually I was creating a 20-intel.conf file in /usr/share/X11/xorg.conf.d/ with the following content:
Section "Device"
Identifier "card0"
Driver "intel"
Option "Backlight" "intel_backlight"
BusID "PCI:0:2:0"
EndSection
This worked until today. Now I realised that Xorg is somewhat ignoring this configuration file. I looked in the wiki and this suggested that any such config files should be in /etc/X11/xorg.conf.d/. I copied the file there and rebooted. I opened a terminal and checked the value of /sys/class/backlight/intel_backlight/actual_brightness. Modified the brightness with the Fn + F6/F7 and checked again and it was controlling these.
But after closing the lid and leaving it for a while, and wakeing up the PC the Fn +F6/F7 keys started controlling /sys/class/backlight/toshiba/ which never worked after sleep. Somehow on wakeup the custom config files are being ignored. It seems this is related to the upgrade to Gnome 3.16. I'm using linux-lts kernel.
How do I make Xorg use intel_backlight instead of Toshiba for brightness control?
Last edited by entodoays (2015-05-18 15:21:04)

It seems that the culprit is /usr/lib/gnome-settings-daemon/gsd-backlight-helper. In this page: http://ubuntuforums.org/showthread.php?p=11910629 there's a procedure to patch the source file (for an older version). There's a section of the code like this:
/* available kernel interfaces in priority order */
static const gchar *backlight_interfaces[] = {
"nv_backlight",
"asus_laptop",
"toshiba",
"eeepc",
"thinkpad_screen",
"acpi_video1",
"mbp_backlight",
"acpi_video0",
"fujitsu-laptop",
"nvidia_backlight",
"samsung",
NULL,
Patching this file, eliminating the toshiba device from the preferred list and adding intel_backlight to it might solve the issue.
On another page, https://github.com/mate-desktop/mate-po … issues/135 they suggest another possible hack: changing the priority of device type
file plugins/power/gsd-backlight-helper.c
/* search the backlight devices and prefer the types:
* firmware -> platform -> raw */
path = gsd_backlight_helper_get_type (devices, "firmware");
if (path != NULL)
goto out;
path = gsd_backlight_helper_get_type (devices, "platform");
if (path != NULL)
goto out;
path = gsd_backlight_helper_get_type (devices, "raw");
if (path != NULL)
goto out;
Changing the order to firmware -> raw -> platform would solve the problem for me too.
Unfortunately I've never done any patching yet. How would I go about it?
Last edited by entodoays (2015-05-12 07:22:06)

Windows 8.1 kills screen brightness control

I have a touch smart 23 computer that came with windows 8.0. An auto upgrade to 8.1 caused the screen brightness control to stop working and the screen stays on super bright. I could not get a response on how to fix so I had to re-install 8.0 which fixed the problem. I set the system to not upgrade without my approval and yet it did it again last week (about 4 or 5 months later). When I have to reinstall 8.0, I have to re-install several primary programs as there are no restore points left except back to factory settings. Question one is - has there been a fix installed on windows 8.1 that will again let me control the brightness on my screen? If not, question 2 is how did the update override my setting to not allow updates to install without my approval. I have a full day of re-installs that I don't want to have to do a third time.

Hi:
You probably have to install the W8.1 graphics driver for your specific model.
Normally when you can't control the screen brightness, that means the graphics driver isn't installed.
As for your second question, that I do not know.

My screen gets dim and the brightness control buttons don't work

My screen is frequently dim. The brightness control buttons display that they are working, but the brightness doesn't actually change. Any ideas why and what I can do?

Thanks for the suggestion. Actually, I had tried that but still had to go into preferences any time I wanted it brighter. After I posted, I found a thread using some different keywords and found that people were having the same problem with OS versions up to 10.7.2 but solved it with the latest update (10.7.3). I just installed it and now seem to be able to adjust the brightness with my keyboard no problem. I appreciate your reply anyway!

My screen brightness control buttons don't work windows 8

my screen brightness control buttons don't work?
the light in the mute button is always on when NOT on mute?
Have set up Win8 3 TIMES but get always same bug agan
Hope someone can help

Hello smarisig. I understand you are not able to control screen brightness from the keyboard on Windows 8. By chance, did you upgrade to Windows 8 from Windows 7? I have located an online forum that contains troubleshooting on this issue: http://thedailybuggle.com/forum/unable-control-screen-brightness-windows-8-a-200.html
The person who posted the issue on this forum had upgraded from Windows 7 to Windows 8, and then this issue occurred. That is the reason I asked if this Windows 8 was upgraded. Regardless, follow the troubleshooting presented and it could resolve the issue for you. If not, let me know and I will continue to research the issue in the meantime. I'm only here to help!
Mario
I worked on behalf of HP.

Broken backlight brightness control

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