Laptop brightness on battery power doesnt work

[junk123]

I have power management set to change the brightness to 50% on battery power. So when I unplug the power it goes to the 50% however when I try and increase the brightness on my Dell E1705 by using Fn+up it doesn't work, it like goes down all the way.

This worked in Feisty so I'm not sure what happened.

[junk123 (junk123-deactivatedaccount-deactivatedaccount)]

Sorry this is in Gutsy, fully updated

[Juan Pablo Salazar Bertín (snifer)]

Confirmed, using Dell Inspiron 9400.
If I kill gnome-power-manager I'm able to change brightness using Fn+Up/Down.
g-p-m version: 2.19.6-0ubuntu4.

[Jacob Emcken (jacob-emcken)]

I can confirm I see this as well on my IBM x40 laptop.

When it occurs I cannot get brightness above the lowest level. When I push "brightness up" (Fn + Home) brightness increase for a second then automatically returns back to lowest brightness almost at once. The indicator (brightness level) which Gnome displays on the screen on to of all applications shows the correct value. It shows the increase of for a moment then returns the indicator to zero.

When I cange power state (pulling AC or connecting AC) for the next "brightness up" presses it behaves a bit different.
The number of presses this goes on varies but it always comes back to the above behaivor.

Here is what happens:
1. time I press brightness up the brightness increase one level and stays there thought the indicator on the screen shows level zero
2. time I press brightness up the brughtness decrease but the indicator on the screen now increase.
From here the behaivor just loops between the two states until it suddenly goes back to staying on brightness zero (including the indicator) and only increase for a moment and then automatically decrease again.

Brightness down allways works as expected :)

[Juan Pablo Salazar Bertín (snifer)]

I'd like to add that using the brightness applet I can successfully change my LCD brightness.

[Evan Carroll (evancarroll)]

confirmed on lenovo X60s, for me the total power scheme is borked, I don't even know where to start on this bug report. The laptop lid-close results in some sort of gdm crash. The brightness randomly drops to 50% in operation. When I open the power-manager, it boosts back up to full, if I slide the dimmer, it dims for one second and dives back down to 50% - for me the lenovo brightness up key works though.

If I unplug the power, and plug it back in, even though my power manager is set to 100% on both profiles, it jumps to 50, and plugging the cord back in will *not* alter it. I have to use kb key to raise brightness.

[Rafael Sachetto (rsachetto)]

Confirmed on Asus F3sc laptop.

When I press Fn+F5/F6 on my Asus laptop the screen gets dark and I have
to run the command gnome-power-manager to restore my brightness to the
normal.

[nanog (sorenimpey)]

Confirmed on dell e1405. Function key up (increase brightness) does not work.
This broke when gnome power manager was upgraded (2.19.6 ubuntu4). Also, confirm that the function keys work properly when power manager is killed.

[Rafael Sachetto (rsachetto)]

Confirm that the function keys work properly when power manager is killed too.

[Baggie (hyperpiper)]

Confirmed on Dell 640m press in the incease brightness button causes brightness to drop to low, increase by one then decrease by one. this continues as long as the button is pressed

[Juan Pablo Salazar Bertín (snifer)]

I think this bug has been introduced in this update (but I could be wrong):

gnome-power-manager (2.19.6-0ubuntu3) gutsy; urgency=low

  * GetBrightness returns an int, not an unsigned int

 -- Matthew Garrett <email address hidden> Wed, 29 Aug 2007 22:06:03 +0100

When g-p-m tries to read my brightness (before setting what it reads to a higher level), I get:

[gpm_brightness_lcd_init] gpm-brightness-lcd.c:496 (20:49:31): Laptop panel levels: 101

(gnome-power-manager:10254): GLib-GObject-CRITICAL **: g_value_set_uint: assertion `G_VALUE_HOLDS_UINT (value)' failed
[gpm_brightness_lcd_get_hw] gpm-brightness-lcd.c:116 (20:49:31): GetBrightness returned level: 0

[Juan Pablo Salazar Bertín (snifer)]

In my up-to-date gutsy, GetBrightness returns uint instead of int:

snifer@snifer-laptop:~$ dbus-send --system --print-reply --dest=org.freedesktop.Hal /org/freedesktop/Hal/devices/computer_backlight org.freedesktop.Hal.Device.LaptopPanel.GetBrightness
method return sender=:1.3 -> dest=:1.31 reply_serial=2
   uint32 100

[Richard Theil (richard-theil)]

Since a recent update, I see the bug on an IBM T41. On "gnome-power-manager --no-daemon --verbose" it outputs:

[gpm_brightness_lcd_init] gpm-brightness-lcd.c:496 (16:17:54): Laptop panel levels: 134648572
*** WARNING ***
[gpm_brightness_lcd_init] gpm-brightness-lcd.c:498 (16:17:54): Laptop panel levels are invalid!

(gnome-power-manager:6019): GLib-GObject-CRITICAL **: g_value_set_uint: assertion `G_VALUE_HOLDS_UINT (value)' failed
[gpm_brightness_lcd_get_hw] gpm-brightness-lcd.c:116 (16:17:54): GetBrightness returned level: 0

Looks like the number of levels is bogus. This value seems to originate in the Hardware Information, where under "Generic Backlight Device" laptop_panel.num_levels already shows "134648572 (0x80692fc)". I'd expect something like "8" or "16".

[theanalogkid (mlyszczek)]

I can also confirm this on my Z61m. It suddenly will drop to the lowest brightness level, and I have to start gnome-power-manager to get it to stay at full brightness.

[junk123 (junk123-deactivatedaccount-deactivatedaccount)]

Bug seems to be back :(