Laptop LCD brightness.

[Capt Turk]

I've come across a number of posts about laptop LCD brightness controls not working.  Mine doesn't work either.  No one seems to have a fix/patch for it.

What I'm wondering, is, does anyone know the memory locations that control it?  I used to know how to program in basic. It has the poke command.  I think I can remember enough so that If I can find out the memory locations, I might be able to write a small program that would control the brightness.  It wouldn't be as convenient as getting a proper patch, but would be better than nothing.
 

[MaddogF16]

Are you running KDE? Mine works great using the power app in the system tray, just open it and adjust right from there.

[AS]

I've come across a number of posts about laptop LCD brightness controls not working.  Mine doesn't work either.  No one seems to have a fix/patch for it.

What I'm wondering, is, does anyone know the memory locations that control it?  I used to know how to program in basic. It has the poke command.  I think I can remember enough so that If I can find out the memory locations, I might be able to write a small program that would control the brightness.  It wouldn't be as convenient as getting a proper patch, but would be better than nothing.
 

The issue with brightness control 'generally' depend from non standard acpi commands used to control brightness, therefore an additional kernel module is required depending on laptop brand/model.

On some Laptop there are also issue related to recognize the keyboard keys used to control brightness.

What brand/model is your Laptop ?

AS

[YouCanToo]

I've come across a number of posts about laptop LCD brightness controls not working.  Mine doesn't work either.  No one seems to have a fix/patch for it.

What I'm wondering, is, does anyone know the memory locations that control it?  I used to know how to program in basic. It has the poke command.  I think I can remember enough so that If I can find out the memory locations, I might be able to write a small program that would control the brightness.  It wouldn't be as convenient as getting a proper patch, but would be better than nothing.
 

Since you didn't mention which laptop and who the mfg was just how do you really expect someone to know the memory location(s) to your specific computer?  You really need to give a bit more information that "it doesn't work" when asking for help.  None of use have crystal balls we use when trying to help out.  The more information that you can give use the faster we can help provide a solution to most problems.

[maxpro4u]

when I press the f7=f8 keys along with the fn key, the brightness goes up and down here-no problem
running kde fully updated

[Capt Turk]

You can too -

From what I remember of my basic programing, the computer and operating system didn't matter for memory locations.  My memory is probably wrong. It usually is.
Sometimes you have to ask the dumb questions first to get enough info to start asking intelligent ones. 
Ok,  info on the system.

Acer Aspire 7741Z-5731
OS is PCLOS 2011
Kernel 2.6.38.8-pclos1.bfs
Gnome 2.32.0

I've run into several articles on how to fix this, but none seem to work for me.  I did find one that had me add a line to the etc/grub/default file.  I turned the brightness all the way down, but then I couldn't turn it up.
I did discover that if I go into Winders and turn the brightness down, then reboot into PCLOS, the brightness stayed down to the level I set in Windows.

[T6]

i was going to suggest you the upgrade kernel suggestion but you are using latest kernel, that fixed this problem for me on my toshiba

what video card do you have on that acer?

[AS]

I've run into several articles on how to fix this, but none seem to work for me.  I did find one that had me add a line to the etc/grub/default file.  

Exactly, there are several report on the net about the following params to be added to the grub file /boot/grub/menu.lst

"acpi_osi=Linux acpi_backlight=vendor"  did you try to add those 2 parameters ?

[maxpro4u]

So when you press fn+arrow L or R nothing happens?

[Capt Turk]

The brightness menu thingy pops up and shows it changing as I press the L/R keys, but nothing changes.

T6 - I have an Intel integrated card.  The hardware lister shows = Core Processor Integrated Graphics Controller


"acpi_osi=Linux acpi_backlight=vendor"  did you try to add those 2 parameters ?
I added the acpi_osi line to the menu.lst.  No change. Was I supposed to change vendor to Intel or something?

What other (2 parameters?)?

[joseucker]

In the file /etc/X11/xorg.conf can you try this?

Section "Device"
Identifier "Default Device"
Driver "nvidia"
Option "NoLogo" "True"
Option "RegistryDwords" "EnableBrightnessControl=1"
EndSection

On my laptop works fine after adding this line.

Regards