Linux - Laptop and NetbookHaving a problem installing or configuring Linux on your laptop? Need help running Linux on your netbook? This forum is for you. This forum is for any topics relating to Linux and either traditional laptops or netbooks (such as the Asus EEE PC, Everex CloudBook or MSI Wind).
Notices
Welcome to LinuxQuestions.org, a friendly and active Linux Community.
You are currently viewing LQ as a guest. By joining our community you will have the ability to post topics, receive our newsletter, use the advanced search, subscribe to threads and access many other special features. Registration is quick, simple and absolutely free. Join our community today!
Note that registered members see fewer ads, and ContentLink is completely disabled once you log in.
If you have any problems with the registration process or your account login, please contact us. If you need to reset your password, click here.
Having a problem logging in? Please visit this page to clear all LQ-related cookies.
Get a virtual cloud desktop with the Linux distro that you want in less than five minutes with Shells! With over 10 pre-installed distros to choose from, the worry-free installation life is here! Whether you are a digital nomad or just looking for flexibility, Shells can put your Linux machine on the device that you want to use.
Exclusive for LQ members, get up to 45% off per month. Click here for more info.
This will sound like a stupid question, but I'm practically getting a tan off my screen. How does one adjust the brightness of the display in a laptop (Fujitsu Siemens Esprimo)running Fedora 8? I've tried using the 2-key function combination that works with various live CD distros no problem, yet on this (permanent) installation, any attempt to dim the (maximally bright) display reverts to maximum again within a fraction of a second. Can anyone assist?
Thanks,
CC.
Last edited by Completely Clueless; 04-02-2008 at 01:57 PM.
Reason: typo
I think the command xgamma could help. Read the manpage I linked and try something like xgamma -gamma 0.5 in a terminal. Can't test it now, but I bet you will figure it out if the command doesn't work
I think the command xgamma could help. Read the manpage I linked and try something like xgamma -gamma 0.5 in a terminal. Can't test it now, but I bet you will figure it out if the command doesn't work
Regards!
Hi there and thanks for the suggestion. Sorry about the delay, but I've been fighting other demons in WhineDos on another machine. :-(
Right! Well, I entered your suggested command above in the terminal and it appeared to have been executed, because it echoed back something like (and i'm paraphrasing) was Red: 1, blue: 1, green: 1;
now Red: 0.5, blue: 0.5, green: 0.5
indicating (to my simple mind at any rate)a halving of the total of white light, but it made absolutely no difference to the screen brightness.
I didn't budget for the cost of welding goggles in my switchover to Linux, so... any other suggestions?
tnx,
CC.
Last edited by Completely Clueless; 04-04-2008 at 05:25 PM.
Reason: misleading terminology
The only problem with changing the gamma is that you are only stopping down the LCD, reducing the amount of light that passes from the CCFL (Cold Cathode Florescent Lamp). This reduces the number of colors, gray scales and range of luminance available to you. It is a lot like turning the contrast on yout television down.
Furthermore, it does nothing to reduce the power used by the backlight thus providing no reduction in heat load, nor does it help your battery life, and it does not inrease your "green" karma.
Most of the laptops I have worked with have (or can have) an entry in the /proc file system that allows the control of backlight brightness
This support can enabled in the kernel. The fact that it dims, and then reverts makes me think this may be enabled. Take a look in /proc and look for things like smi, Fujitsu, acpi. Drill down and see if you can find something related to brightness. If you do, use cat to look at the current value, and echo (see above) to try to change it.
The only problem with changing the gamma is that you are only stopping down the LCD, reducing the amount of light that passes from the CCFL (Cold Cathode Florescent Lamp). This reduces the number of colors, gray scales and range of luminance available to you. It is a lot like turning the contrast on yout television down.
Furthermore, it does nothing to reduce the power used by the backlight thus providing no reduction in heat load, nor does it help your battery life, and it does not inrease your "green" karma.
Most of the laptops I have worked with have (or can have) an entry in the /proc file system that allows the control of backlight brightness
I'm afraid this doesn't appear applicable. My laptop doesn't have a backlit LCD screen (haven't seen one of those for years) but rather a TFT one.
Thanks for trying to help, though.
TFTs are great --most modern laptop displays are TFT. The TFT LCD has greater transmissivity of light because TFT structure provides a greater optical aperture -- but it is not self luminescent. TFT (Thin Film Transistor) LCD panels are still just programmable attenuators that require a backlight. Predominately, these backlights are CCFL, although LEDs are coming on strong. For now CCFLs hold the efficiency and cost edge.
The only technologies that I know of that do not require a backlight are LED matrix, Plasma, or OLED. The first two are power hungry and are not applicable to laptops, OLEDs are not quite ready for production.
Last edited by ewaller; 04-05-2008 at 07:52 PM.
Reason: typo
TFTs are great --most modern laptop displays are TFT. The TFT LCD has greater transmissivity of light because TFT structure provides a greater optical aperture -- but it is not self luminescent. TFT (Thin Film Transistor) LCD panels are still just programmable attenuators that require a backlight. Predominately, these backlights are CCFL, although LEDs are coming on strong. For now CCFLs hold the efficiency and cost edge.
The only technologies that I know of that do not require a backlight are LED matrix, Plasma, or OLED. The first two are power hungry and are not applicable to laptops, OLEDs are not quite ready for production.
Oh! Sorry I had no idea they functioned in this way. So the screens are always maximally backlit? Crumbs, that's a really inefficient set-up, I must agree. I always wondered why turning down the brightness never seemed to make any real impression on battery life!
Thanks for the lesson; I'll give it another shot and post back in due course!
LinuxQuestions.org is looking for people interested in writing
Editorials, Articles, Reviews, and more. If you'd like to contribute
content, let us know.