brightness Applet very slow and processors getting bisy when try adjust LCD brightness

[Dmitriy]

When I adjust LCD brightness its happen very slowly and getting processors on 100%. However is working!

[Henrik Rydberg (rydberg)]

I can confirm this problem on a Macbook Air 1,1, running Intrepid with kernel 2.6.27-5-generic.

After starting X, nothing happens when pressing the LCD panel keys - you think. After about one minute (!), the key presses you already forgot about suddenly takes effect, and the screen brightness is adjusted. From this point on, pressing the LCD panel keys works well and as you would expect. Also after several suspend/resume cycles, the keys stay responsive.

During that first odd startup time, pressing the volume keys works, but pressing the keyboard backlight keys does not work. However, after the system is done doing whatever it does that first minute, also the keyboard backlight keys work well (note to reproducer: keyboard backlight does not yet work on MBA, am sending my fix upstream).

Because of the connection to the keyboard backlight, which is controlled via hal and a proper fdi configuration, I suspect the culprit here is hal. I do not know what part of power management that eventually ends up modifying the LCD brightness, but since there is no laptop_panel capability listed when running hal-find-by-capability, I suspect the minute-long wait could have something to do with patient searching for the right device.

Am I wrong?

[Jeremy Leland (iggames)]

Interesting, I have this issue in reverse.

I'm running Intrepid 2.6.27-7-generic on a Thinkpad T61. When the machine first boots, the brightness keys are responsive. After suspending and reviving, however, the brightness keys are no long resonsive. The first press will take effect and bring up the dialog (with the brightness icon and proress bar), but subsequent presses do not reliably take effect (and if so, not for several seconds). I don't see any jumps in the CPU monitor.

The brightness applet (in the panel) responds as expected.

[Rami Al-Rfou' (rmyeid)]

It takes too much time to get the response of the brightness applet. This is annoying. However, nothing change for the processor usage. I attached the needed log according to https://wiki.ubuntu.com/DebuggingHal

[Rami Al-Rfou' (rmyeid)]

All the information needed is available attached in my comment. I face the problem everyday :(

[Pedro Villavicencio (pedro)]

Thanks for the report, Could you check with top what's using a lot of cpu? There's a bug open about a similar issue for an intel video driver, which video card do you have and which driver are you using?

[bomanizer (janne-matolaatikko)]

Hi, I'm having this issue also on a T61. It seems to happen after resume, as Jeremy wrote. Running top at the same time as fiddling with brightness puts Xorg on the top of the list.

[bomanizer (janne-matolaatikko)]

Oops, forgot: my graphics card is Intel X3100.

[Georg Schmidl (vicox)]

I'm having this problem too, on the Dell Mini 9. The applet is very slow and unresponsive, while Xorg eats about 30% CPU.

[Cachapa (cachapa)]

Same problem on a Samsung NC10 netbook.

[Henrik Rydberg (rydberg)]

If your graphics cards have a high number of brightness levels, chances are the problem is related to https://bugs.launchpad.net/ubuntu/+source/gnome-power-manager/+bug/289520. Although that particular bug has been fixed, the problem is still in effect when adjusting the brightness with the keyboard. A patch to the karmic g-p-m is attached, which might fix the problem for you. It can be installed from the mactel repository also (2.27.5-0ubuntu2~mactel1). Visit https://launchpad.net/~mactel-support/+archive/ppa for details.

[Victor Vargas (kamus)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. You reported this bug a while ago and there hasn't been any activity in it recently. We were wondering if this is still an issue for you. Can you try with the latest Ubuntu release? Thanks in advance.

[Alan Fischer e Silva (alanfischer85)]

I am using the latest ubuntu 10.04 alpha 3 and I can still see this problem. It is very slow and processors get busy when changing the brighness level. I had to deactivate the "Dim display when idle" option because of that.

I have a HP Pavilion dv 2000.

[Eric Drechsel (ericdrex)]

This report isn't incomplete. It's also not hardware-specific. Brightness controls are S-L-O-W. This is because g-p-m waits for the notification to display before making the adjustment (synchronous). To make is responsive g-p-m should display the notifications asynchronously and then go ahead and make the adjustments right away.

[Ali Utku Selen (auselen)]

I've made a personal build of gnome-power-manager with fixes to two bugs; #535097 and #261450.
If you feel like experimenting, you can add related ppa via "sudo add-apt-repository ppa:auselen/ppa", then "sudo apt-get update" and finally "sudo apt-get upgrade". On a fresh system, this should just change g-p-m.

[Launchpad Janitor (janitor)]

[Expired for gnome-power-manager (Ubuntu) because there has been no activity for 60 days.]

[svens (svens)]

I'm experiencing the same issue.