screen brightness notification out of sequence with keypresses on Dell XPS M1530

[Rocko]

Binary package hint: notify-osd

When I press the screen brightness adjustment keys on my Dell XPS M1530, the screen brightness changes but the notify-osd display is often out of sync (but not always) - it instead displays what the results of the previous keypress would have been.

eg I press brightness-down and then brightness-up. On the second keypress the screen brightness goes up as expected, but notify-osd indicates that it has gone down. If I press brightness-down, the changes are that notify-osd will now display the brightness-up operation.

Version info:

Ubuntu 9.04 beta
kernel 2.6.28-11-generic amd64
notify-osd 0.9.6-0ubuntu2

[Mirco Müller (macslow)]

I've only a Lenovo X61t here to test. On this laptop the screen-brightness changes and the display from notify-osd (triggered by g-p-m) are perfectly in sync. The only "out of sync"-case I encountered is when I hit brightness-up/down very fast (e.g. 3 keystrokes a second), not all keystrokes are not caught be the system and therefore the brightness is not changed every time. But when the screen-brightness changes the brightness-indicator rendered by notify-osd is updated in-sync always.

[Rocko (rockorequin)]

It works fine on a Dell Inspiron 8600 with an ATI graphics card and the open-source driver, but I still can reproduce the out of sync problem easily on my Dell XPS M1530 with an nvidia card and the nvidia driver. Is there more information I can provide?

[Andreas Berger (andi-berger)]

constantly and totally out of sync on Acer Travelmate 4650

the potential number of steps does not even match. my display has 15 steps of brightness, the animation seems to have twice as much. with the old notification system the number of steps matched, but was mostly out of sync as well.

please tell me if i should provide more hardware information

[Rohan Garg (rohangarg)]

Hi,i have a XPS M1530 and the notification is out of sync when i log 3 key presses quickly
Also If you use kpowersave along with notify-osd you get only 3 levels of brightness on a M1530 whereas without kpowersave running i get 6 levels of brightness

[Simon (simschi)]

Hello!
On my Acer Travelmate 3020 it seems like I have a step-less brightness control (would guess >150). In fact I have 15 steps as well. And its also out of sync.

Does anybody know where I can set the number of steps manually?

[Miklos Juhasz (mjuhasz)]

Fully updated Ubuntu 10.04 with nvidia driver. The notification is out of sync here as well.

[Miklos Juhasz (mjuhasz)]

I managed to fix the brightness issue on my Dell M1530, Ubuntu 10.04. The Fn key worked but the notification was out of sync. Adding the acpi_backlight=vendor to the grub command line solved the problem.
I edited the /etc/default/grub file, GRUB_CMDLINE_LINUX row. Remember to run sudo update-grub2 and sudo update-initramfs -u after editing the grub file. After reboot it will take effect.

[chreko (chreko)]

I am also affected by this bug. I am using Ubuntu 10.10 (AMD64) on a HP ENVY 14 with an Intel i5 CPU (and integrated GPU).

The fn keys (fn+f2 and f3) for controlling the brightness do work. However, the notify-osd is completly out of sync; while it could only be increased and decreased in five steps, the brightness itself could be changed in ten steps. The brightness could also be modified by editing "/sys/class/backlight/acpi_video0/brightness" by changing the existing number with another between 0 and 10 (see http://ubuntuforums.org/showthread.php?t=1593079).

Adding "acpi_backlight=vendor" as suggested did however deactivate the fn keys (fn+f2 and f3) completely and /sys/class/backlight appeared to be empty. Ubuntu on the other hand did start with full bright screen but no way to modify the brightness.

Something that could be interesting is the following: Settings in gnome-power-manager related to the backlight has no real effects, except on notify-osd. For example, although brightness_dim_battery (LCD dimming amount when on battery) was set to 50, unplugging the notebook had no effects on the brightness, but notify-osd appeared to be reduced by a half.