Can't adjust brightness on Toshiba A100

Mr. Alex · 11-26-2010, 09:42 AM

Nothing I found works. I need to reduce brightness of Toshiba Satellite A100, the screen is too bright. Gnome on Arch, "xf86-video-intel".

Fn buttons don't work.
"echo NNN > /proc/acpi/video/.../brightness" doesn't make any change.
Gnome power manager doesn't affect anything...
Brightness applet does nothing.
xbacklight is not even in Arch repos...

Please help.

catkin · 11-26-2010, 09:53 AM

What does cat /proc/acpi/video/GFX0/LCD/brightness do?

alan_ri · 11-26-2010, 10:42 AM

Hi!

It looks like we have the same laptop!

I must say that lately I've been testing some distros on my Toshiba and on each one Fn keys did work. Even the multimedia keys too. So this is some "Arch thing", but I'm not using Arch and I'm using Xfce at the moment. Our laptop is supported. This used to be a problem with Toshiba laptops which did not have Phoenix BIOS, thus another project was created fnfx.

Try to change something in GConf key /apps/gnome-power-manager/

Quick Google search pointed to this;

Quote:

ACPI

First of all start /etc/rc.d/acpid and add it to DAEMONS in rc.conf.
Special buttons

Some special buttons work out-of-box, some not. Here is the list:

Button Comment
Power Recognized by ACPI, add event to /etc/acpi/events, see below
Web Works (xbindkeys)
Music (?) Doesn't work
Play Works (xbindkeys)
Stop Works (xbindkeys)
Rev Works (xbindkeys)
Ffd Works (xbindkeys)

Fn+Esc (Mute) Works (xbindkeys)
Lock Works (xbindkeys)
Magnify Doesn't work
Suspend to RAM Doesn't work
Suspend to disc Doesn't work
VGA switch Works out-of-box
Brightness Works, module "video"
WIFI Doesn't work (there is a switch, so what for?)
Touchpad on/off Doesn't work
Num Lock/Scroll Lock Work

Volume knob Works (xbindkeys)

And that is from Arch's wiki. Check out this guide here.

Mr. Alex · 11-26-2010, 11:55 AM

Quote:

Originally Posted by catkin

What does cat /proc/acpi/video/GFX0/LCD/brightness do?

Code:

# cat /proc/acpi/video/GFX0/LCD/brightness
levels:  0 20 40 60 80 100
current: 100

On the tty1 there is an error message after system booting is complete:

Code:

Cannot open display: default display

Maybe this is part of the reason?

Mr. Alex · 11-26-2010, 12:05 PM

alan_ri, did what you wrote. Gconf (brightness = 50).
acpid also. Nothing.
Brightness is still too high, can't work like this.

alan_ri · 11-27-2010, 12:38 PM

Well, all that sounds weird to me.

The display error, try to set $DISPLAY variable with:

Code:

export DISPLAY=:0.0

As I said, I'm not using Arch an GNOME at the moment, so it's hard for me to give some advise at the moment, but if I think of something, I'll let you know.

Few ideas I have right now;
You could login without X and then start it with:

Code:

startx

...if you haven't already done so and look for the might be errors.

Check what modules Arch uses in the kernel for Toshiba laptops.

What do you get when you run:

Code:

whereis fnfxd

And what's your kernel? Sometimes with different kernel, things work.

Mr. Alex · 11-29-2010, 12:01 PM

> export DISPLAY=:0.0
And it shows "Can't open display :0.0"...

> You could login without X and then start it with: startx
Will try.

> Check what modules Arch uses in the kernel for Toshiba laptops.

Code:

# modprobe toshiba_acpi 
FATAL: Error inserting toshiba_acpi (/lib/modules/2.6.36-ARCH/kernel/drivers/platform/x86/toshiba_acpi.ko): No such device

> whereis fnfxd

Code:

# whereis fnfxd
fnfxd:

> And what's your kernel? Sometimes with different kernel, things work.
2.6.36.1-3.

Mr. Alex · 11-29-2010, 12:09 PM

startx doesn't load X:

Code:

[    24.402] (II) LoadModule: "fbdev"
[    24.403] (WW) Warning, couldn't open module fbdev
[    24.403] (II) UnloadModule: "fbdev"
[    24.403] (EE) Failed to load module "fbdev" (module does not exist, 0)

alan_ri · 11-29-2010, 02:48 PM

Don't know why, but it looks like Arch is missing some modules. Install x11-drivers/xf86-video-fbdev. Try startx again.

Then try:

Code:

echo "brightness:50" > /proc/acpi/video/GFX0/LCD/brightness

I'm on Debian "testing" on my laptop now and here everything works. I will check my modules etc.