brightness-keys react slowly

[Richard Jonsson]

When pressing fn+brighten, fn+darken on laptop, the brightness first gets adjusted, then the osd pops up and restores previous setting and after a delay changes it again. If pressing rapidly, brightness alternates between two strengths until osd-control has caught up.
Changing through /proc/acpi/video/VGA/LCD/brightness has a delay too, but not close to the long delay when changing through the brightness keys.
Sometimes when changing with keys, the control gets confused and darkens instead of brighten, or vice versa.

cat /proc/acpi/video/VGA/LCD/brightness:
levels: 100 60 20 28 36 44 52 60 68 76 84 92 100
current: 76

1. hardy 8.04, intrepid 8.10
2. unkown
3. Change of brightness without delay
4. Change of contrast has delay, and also jumps between levels.

[arno_b (arno.b)]

Thank you for taking the time to report this bug and helping to make Ubuntu better.
This bug did not have a package associated with it, which is important for ensuring that it gets looked at by the proper developers. You can learn more about finding the right package at https://wiki.ubuntu.com/Bugs/FindRightPackage.
I have classified this bug as a bug in acpi.

[arno_b (arno.b)]

To be able to fix the hotkeys on your laptop we need three things:

   1. What the key *should* do.
   2. What keycode (magic number) the key produces on your laptop.
   3. How to identify your laptop by the manufacturer and model.

You can see the following documentation to know how to do that:
https://wiki.ubuntu.com/LaptopTestingTeam/HotkeyResearch

Set to incomplete until we have more information.

[Richard Jonsson (richard-jonsson-bredband)]

1. What the key *should* do.

Key1: Brightness down, darken backlight, a sun with a down-arrow to the right
Key2: Brightness up, brighten backlight, a sun with an up-arrow to the right

2. What keycode (magic number) the key produces on your laptop.

Key1: XF86MonBrightnessDown
Key2: XF86MonBrightnessUp

3. How to identify your laptop by the manufacturer and model.

Hewlett-Packard
HP Pavilion dv2000 (RN081EA#UUW)
F.34

[Victor Osadci (victor-os)]

I have the same problem on a HP 6820s.

Hewlett-Packard
HP Compaq 6820s
F.09

[Richard Jonsson (richard-jonsson-bredband)]

Actually, I think it's kernel-related this time around. It takes about as long to change brightness in a terminal as using hotkeys.

# time echo 84 > /proc/acpi/video/VGA/LCD/brightness

real 0m0.763s
user 0m0.000s
sys 0m0.000s

That wasn't the case last time around (the old bugreport).

[Richard Jonsson (richard-jonsson-bredband)]

Sorry, wrong bug #