# Reduce Laptop LCD brightness don't work

## MAGGETTE

Hi, I'm trying to change the brightness of my laptop LCD but it's not working. 

- The laptop is a HP 6730s with intel video card

- kernel gentoo-sources-2.6.27-r7

- hal-0.5.11-r4

I can change the value manually in proc but the brightness doesn't change.

```
# cat /proc/acpi/video/GFX0/DD04/brightness

levels:  100 51 30 37 44 51 58 65 72 79 86 93 100

current: 51
```

To make my brightness Fn keys work I used this patch. Now I have the keycode with xev but still not working

http://www.nabble.com/HP-Compaq-6730s-keymap-patch-td19639167.html

```
[hal-info-keymap-hp-6730s.patch]

diff --git a/fdi/information/10freedesktop/30-keymap-hp.fdi b/fdi/information/10freedesktop/30-keymap-hp.fdi

index 8f71267..c4871c0 100644

--- a/fdi/information/10freedesktop/30-keymap-hp.fdi

+++ b/fdi/information/10freedesktop/30-keymap-hp.fdi

@@ -27,6 +27,12 @@

           <append key="input.keymap.data" type="strlist">e008:presentation</append>   <!-- Presentation -->

           <append key="input.keymap.data" type="strlist">e059:info</append>   <!-- I key -->

         </match>

+        <match key="/org/freedesktop/Hal/devices/computer:system.hardware.product" contains="6730s">

+ <!-- HP Compaq 6730s -->

+          <append key="input.keymap.data" type="strlist">e012:brightnessdown</append> <!-- FnF7 (brightness down) -->

+          <append key="input.keymap.data" type="strlist">e017:brightnessup</append> <!-- FnF8 (brightness up) -->

+          <append key="info.capabilities" type="strlist">input.keymap</append>

+        </match>

  <match key="/org/freedesktop/Hal/devices/computer:system.hardware.product" contains_outof="2510p">

           <!-- The 2510p seems to be unique in having a touchpad disable button despite being an enterprise model -->

           <remove key="input.keymap.data" type="strlist">e059:info</remove>

```

output from xev when pressing Fn keys

```
KeyRelease event, serial 34, synthetic NO, window 0x3a00001,

    root 0x79, subw 0x0, time 4260939, (-467,524), root:(335,549),

    state 0x0, keycode 232 (keysym 0x1008ff03, XF86MonBrightnessDown), same_screen YES,

    XLookupString gives 0 bytes:

    XFilterEvent returns: False

KeyPress event, serial 34, synthetic NO, window 0x3a00001,

    root 0x79, subw 0x0, time 4263493, (-467,524), root:(335,549),

    state 0x0, keycode 233 (keysym 0x1008ff02, XF86MonBrightnessUp), same_screen YES,

    XLookupString gives 0 bytes:

    XmbLookupString gives 0 bytes:

    XFilterEvent returns: False

```

It recognise XF86MonBrightnessUp and XF86MonBrightnessDown but it does nothing...

I found a possible solution for a similar laptop 6735s

http://www.linlap.com/wiki/HP-Compaq+6735S

```
dbus-send --print-reply --system --dest=org.freedesktop.Hal /org/freedesktop/Hal/devices/computer_backlight org.freedesktop.Hal.Device.LaptopPanel.SetBrightness int32:2
```

But it doesn't work either

I tried several things but with no results. Help please!

----------

## MAGGETTE

I tried to modify the brightness in the sys but still not working

```
# echo 1 >  /sys/class/backlight/acpi_video0/brightness
```

maybe is the xf86-video-intel driver? I'm using the last version xf86-video-intel-2.5.1-r1

----------

## MAGGETTE

I found out a solution using... Windows!!! in wine

http://ubuntuforums.org/showpost.php?p=3180032&postcount=15

The program is http://www.softpedia.com/get/Tweak/Video-Tweak/Gamma-Panel.shtml

But I hope to solve it with linux

----------

## MAGGETTE

I finally got a working solution from here

https://bugs.launchpad.net/ubuntu/+source/xbacklight/+bug/173652

```
emerge xbacklight

xrandr --output LVDS --set BACKLIGHT_CONTROL native

xbacklight -dec 10 # to Up brightness by 10

xbacklight -inc 10 # to Down brightness by 10

```

Now let's try to use the Fn keys to do this work

----------

## MorpheuS.Ibis

I use xbacklight with my HP 6730b and it works just right (using xbindkey to bind the command to button), only it doesn't work without X running

----------

## Tae_kyon

I have a 6730s HP laptop, and I'm having quite a few problems getting the kernel just right.

Could someone (such as Maggette) with a 6730s HP laptop be so kind as to send me their .config file so I can compare it with mine?

Thank you very much.

----------

