General :: Power Management - How To Switch Off Backlight
Apr 25, 2011
On a couple of Linux laptops I have the built in screen never turns off it's backlight, regardless if a 'black screen' sort of screen saver is activated (this both for a laptop running an X-based desktop as well as for a laptop only having a text console) or if I even close the lid of the laptop (looking carefully in the dark, I can tell that the screen still has the backlight on, even if the laptop "know" it is closed).
This is a bad thing for a couple of reasons:
It wastes power
It generates heat which when the laptop lid is closed increases the cooling need (the fan goes on more often etc).
Backlights have limited lifetime like all electric components and IIRC, the less a backlight is turned on, the longer it will last. So, what is the best approach (considering a Gentoo with a 2.6.36 kernel) to remedy this? I recon that there probably are two approaches:
One for text-only laptops which never displays a desktop, e.g a laptop sitting there acting like a firewall or server
one for those running a Gnome/KDE/XFCE desktop (and a SLIM or GDM display manager).
The laptops I have in mind is a Dell Latitude CPi (built 1999, yes, it is from another millenea), a Compaq Armada M700 (built 2001) and a Dell Latitude D630. If this can be accomplished only by configuring things in the Linux OS (be it kernel setup or editing config files) without touching anything in BIOS, that would of course be preferable.
I'm fairly used to working with Fluxbox.There,if I want to let myself suspend the computer, all I have to do is add something like Code:[exec] (suspend) {sudo /usr/sbin/pm-suspend}to my .fluxbox/menu and it works like a charm, after having added me to the sudoers. I nstalled openbox earlier today because I was having some font rendering issues in flux and I've been trying to find a way to add something similar to my menu without success. I added this to .config/openbox/menu.xml:
I've recently installed Ubuntu 10.04 and found the following problem: power management doesn't appear to be working. If I'm away from my computer for only a few moments, the screen is on dim when I return and I have to log on again. I've set the following states in Power Management: NEVER SWITCH OFF SCREEN and haven't ticked the DIM WHEN IDLE BOX. Can anyone help with this problem - it's infuriating. Meanwhile, I've gone back to Ubuntu 9.10 ...
I have to questions: I am new with Linux and using ubuntu on my laptop computer. when i reopen my leptops cover after i closed it, meaning - putting computer to sleep, every thing is working, but the screen is black and nothing is seen. No matter what i tried to do, i cant make it to "wake up".
Using the computers battery, with no electric supply, the battery time is only half of what i get when using windows. i tried using less lumination but it didnt seem to help.
On the last release, I had this app installed where I could pick my power profile. I could use power conservatively, and performance would suffer a bit, but longer batt life,or I could have it automatically detect, or I could have the apps use all the power they want and then some. I'm looking to reinstall that app. What was the name of it?I can't remember, and so far, can't find.
Since I own one of those Centrino based Core 2 notebooks that create annoying buzzing noises when idle (= entering C3 or C4 power saving states), I'm looking for a program that creates artificial CPU usage. It should allow me to limit the CPU usage to a certain percentage (I know that there are a lot of easy ways to create 100% usage ;-).
Another option would be to disable the C3 or C4 states, but in newer kernels the sysfs interface to set the max_cstate on-the-fly was removed for some reason, and I don't always want to reboot after switching from AC to battery (and vice versa).
I've got a rather annoying problem with OpenSUSE 11.1 x86_64, I can't turn off the display power management! I've tried from the KDE 3 and 4 settings as well as GNOME, and finally YaST2. There's nothing in monitor's controls (the buttons on the monitor itself). The actual GUI controls in KDE/GNOME/YaST2 work (as opposed to being grayed out or disabled) and the system doesn't complain when I hit apply/OK, but every time I disable display power management, I wait about 15 minutes and sure enough, the screen blanks. I've checked and made sure the screen saver is disabled, I've looked for a setting to change in the YaST2 sysconfig editor and the kernel settings app, but can't seem to find anything. The only other thing I can think of is to try the acpi=off kernel boot option. I'd rather not resort to that. Anyone know if there is some super secret hidden setting somewhere that might be overriding everything else? Could this be some sort of ACPI incompatibility issue?
I have recently loaded Ubuntu 9.10 which runs perfectly, except for the power management system.I go into the GUI power management screen and tell it to use the screen-saver after ten minutes, but NEVER suspend/ hibernate but it suspends/hibernates anyway,sometimes after an hour, sometimes hours later.Is it possible to keep the screen-saver but disable the rest of the power management system?
I have selected to power down the monitor after 30 minutes, and suspend the computer after an hour. It does not work. With Beagle not running (more below), the monitor powers down after 30 minutes as expected. But then later (probably after an hour?) it powers up again and stays that way. Not exactly what I envisioned.I have removed Beagle from the set of running processes. The process list ("ps ax") shows Beagle as a serious consumer of CPU time, far more than any other process. (At termination it was at 500:00; the next most hungry process was /usr/bin/Xorg at 10:00. Most barely get over 0:01.) It introduces these problems:
1. after some amount of system idle time (it is about 5 - 10 minutes) Beagle starts consuming vast wodges of CPU time. I have dual core AMD 5200; both CPUs run up to about 70% usage until I do anything, like move the mouse. Then the usage drops back to the usual 5 - 10%. 2. When Beagle is thrashing the CPUs, the power management monitor thinks the system is busy. And powers down nothing.
However, again, that's just a guess from what would make sense.
So my first question is, is there a way to know this information, and is there a place were these critical points are set, or are they all from the UPS. I'm guess there are some settings somewhere because not all UPSs are going to be able to supply this information. Some may only supply a battery level or some just a warning message so there must be some configuration for this somewhere.
My 2nd question is a probably a little harder to know the answer to. After getting this to work I wanted the added functionality of nut so I installed it and got it working and it uses the On UPS Power panel as far as I can tell.
Through all the nut documentation it talks about powering down on once the battery level reaches the critical point (I assume that is "When UPS power is critically low"). I don't see anywhere however where it mentions handling "When UPS power is low" so now the question comes up, will it have any effect at all with nut installed, i.e. what will happen?
Of course I can just "pull the plug" and start finding this stuff out but Linux is all about having the information and "knowing" (assuming all works as it should) I am asking to find out where this information would be -- and become smarter for it
Alright this is not a huge issue but a rather annoying one. I hook my laptop up to my lcd to watch movies all of the time. The problem is though I have selected and reselected many times for the screen to not power off after so many minutes of inactivity. But for some reason it doesnt work. If i set it to an 1 it still like every 5 minutes turns off my screen. Im running 9.10 on a toshiba satellite with an intel graphics card.
I have a laptop with 10.04 installed. When it is plugged in with AC Power, the screen fades black after a few minutes and locks up after about 10 minutes (shows a dialog for passwd when back).This gets really annoying when listening a movie or just reading text.System->Preferences->Power Management is set to "never" for everything.gconf-editor->apps->gnome-power-management is set to "0" for everything finishing with *_ac.
I am wanting to completely disable Power Management, can I do it through the GUI? I am a former OpenSuSE user & am use to YaST. So it is a little hard finding ways to edit some settings.
I just did a fresh installation of Kubuntu 10.10 on a laptop last night, which has a 1.6GHz Intel Core Duo CPU.
I was very disappointed to find that there appears to be no way to configure CPU frequency scaling in the System Settings. There were options for this in 10.04.
I prefer to have the CPU running at maximum speed when running on A/C. In Maverick, however, I have had to resort to installing cpufreq-utils, and setting the CPU cores to 'performance' from the command line.
I like this laptop a lot, but even many simple games run sluggishly if the CPU cores are not set to run at max GHz. (As a matter of fact, this machine is much more sluggish even with CPU cores running at maximum in 10.10 than was the case in 10.04.)
I wonder why such an important option would have been removed from the power management settings?
when i get the Graphics device driver on, then the power management not work. it can not change the CPU frequencies, and it can not change the LCD backlight and save the change. I try a lot, install laptop-mode-tools,and change thd setting, it still not work...
ubuntu 10.04.1 linux 2.6.32-27-generic i5 460m CPU ATI HD5470
Ok, I am running a file server that can be accessed throughout the house. I was able to successfully wake from suspend and it works beautifully. Now what I need the computer to do is go to sleep after lets say 30 minutes of inactivity so that I never have to touch the computer and it will use minimal power until I need it.
Anyhow, I tried to set the settings in Power management and the only thing that happens is the display turns off. the suspend on the desktop works fine, I can type in sudo pm-suspend and that works fine. but the computer just wont go to suspend automatically by way of the power manager.
I have tried changing the /etc/pm/config.d/00sleep_module to say SLEEP_MODULE="uswsusp", but that only made the computer go into some crazy linux mode that I had to reboot from. I had to change SLEEP_MODULE="kernel" (actually, I left it blank as it is the default).
I also turned off my screensaver so there wouldn't be any confusion from that.
I also ran cat /var/log/pm-powersave.log and I got a long list with the following being one of the main texts that kept repeating. "/usr/lib/pm-utils/power.d/sched-powersave false:**sched policy powersave OFF"
I've got a new netbook - Dell Inspiron mini 1011. I have installed slackware 13 on it. According to dell's website its battery should last up to 9 hours:Quote:Mini 10 offers up to 9.5 hours of battery life1 to keep you on the go.I understand that it depends on a variety of factors and these are just testing estimations that will probably never be achieved IRL.For 95% of the time I don't run X on it. Just emacs (gnus), nethack, elinks. If I do run X, it's fluxbox. The average battery time is 2hrs - 2.5hrs. I understand that Slackware 13 is not designed specifically for netbooks, but 2hrs is way off the 9-hour estimation. Either the battery is faulty, or it's the power management issue. Before I deal with the battery, I'd like to ask you for some suggestions on improving the power management. The acpi and acpid are installed on the system. Are there any packages that would improve the battery performance? Or perhaps some config options?I believe that recompiling the kernel would improve it, wouldn't it? What options I'd have to set/unset?P.S.Unfortunately, once I checked the netbook is ok, I removed WinXP that came with it, so can't compare with it.
This is very likely a silly question but .. where is the power management setup in KDE? I have set it up before in Slackware 13.1 but now that I'm running 13.37 I'd like to set it up again but can't seem to recall where to set it up.
it doesn't do anything critically wrong.it shuts down, starts up, suspends, restarts, etc, rather well.only thing is that, altho' I set the settings to never hibernate and to never put the display to sleep, it does. I't's annoying, since I can't whatch a movie in peace, for instance.
When I change the "Put display to sleep when in active for" it seems to make no difference. The screen goes to sleep when it wants. Some times in the middle of watching a dvd (after about 10 mins when it is set to 1 hour).Could this be done by terminal, perhaps there is a problem between entering in the GUI and actually telling the machine.
I installed Fedora 13 (KDE) version: Linux version 2.6.33.5-124.fc13.i686.PAE latptop: toshiba satellite C650 - intel core i3 I have few problem, one of them is the power management it seems the power management can't see the battery therefore not battery status. power profile isn;t working. after shutting down the system, the computer stays on (screen, hdd ..etc) until I press the "turn on button". also I cant change the screen brightness using power management..its fixed.I dont know whats the problem and i dont know how to fix it.
I just did an upgrade from F13 to F14.[*] Now, power management (in Gnome) does not work any more. For example, when pressing the power button, there is just a 'Cancel' button (no button for shut down, suspend, hibernate), in Gnome menu there is no possibility to shut down, and in 'gnome-power-preferences' most options do not work at all. For example, there is no other option than 'Blank screen' for 'When laptop lid is closed' action. When starting 'gnome-power-preferences' with '--verbose' parameter, I get following error messages:
I've got openSUSE 11.4 64 bit system with stable 2.6.38 kernel and KDE 4.6.3. Problem is that when I want to change some settings in the power management (like brightness, screen energy saving time-off, display dim), they doesn't seem to save, even after the X restart and full reboot. It's seems like screen energy saving is set permanently for couple of minutes, don't matter what time do i set, it just discards my settings, even they are correctly viewed in the gui.
I've just installed openSuSE 11.2, and I need to disable the feature that causes the laptop to suspend when you close the lid (and it's plugged in to the wall). I've already done this for my user profile, and I've attempted to do it for the root profile, as well, but when the GDM login screen is shown, the laptop still suspends when you close the lid.
After I have installed the Education package I cannot put my HP Pavilion laptop to sleep mode. I opened the Power Management and I can see the red light next to "CPU can be turn off". Also, when I close laptop lid it doesn't go to "Suspend to RAM" mode it still spin the fan.
I have an issue where the screen on my laptop will not shut off with the power management tool. The Default Power Manager does not have an option for this.My screen will go blank after a set amount of time, but the lcd-backlight will remain on. I would want the power manager to shut the screen off completely (including turning off the lcd backlight) without shutting down the computer it-self. So the computer can continue to do what I left it to do in the case I forget to close the lid. With the screen shut off completely, will preserve the life of the back light and reduce power consumption.
Is there a better power manager app that will allow me to do this a tweak to the existing default power manager that will allow the functionality I am seeking? laptop was perfectly able to do this under a win-xp environment, so I know the machine is physically capable of doing this. Note: My WinXP OS and Ubuntu OS are on seperate physical drives so there is no dual boot issues. So when I am using one there is no trace of the other present
when I boot up ubuntu, the suspend and hibernate buttons will be missing and the alsa stuff wont work. When I select shutdown or restart or log out from the power menu ( the one that's missing the 2 buttons) it only logs off the user. I've tried reinstalling the kernel and updating grub for a solution to no avail. The only way to shutdown the system when this occurs is through a sudo halt command in terminal. I may have to use the command a few times until the computer will boot with sound and all of the suspend/hibernate buttons in place.
I have Lucid Lynx with Gnome and Kernel 2.6.32 installed. Which probelms can I get if I disable Power Manager (Power management daemon) from the startup?
BTW does Code: xset -dpms s off do the same thing like disable Power Manager in the Starup Applications or DPMS is just for the Monitor?
I am having some serious speed/connection issues with my laptop's WiFi card, and it has been suggested to me to disable power management for it, just as an experiment. However, when I run "sudo iwconfig wlan2 power off," I receive the error:
"Error for wireless request "Set Power Management" (8B2C) : SET failed on device wlan2 ; Operation not permitted."
