adding "acpi_backlight=vendor acpi_osi=linux" to grub boot options:
a. fully fixes this problem in a Dell Inspiron 1545 running 14.04 (all
behavior normal and as expected, including indicator popups for brightness
adjustment)
b. partially fixes the problem in a Dell Inspiron 1440 running 12.04 (full
access to all brightness levels via dedicated buttons, indicator pops up
but does not visually exhibit a brightness level change)

ethan

“A society grows great when its elders plant trees whose shade they know
they shall never sit in.” -- an ironic Greek proverb


On Sun, Aug 30, 2015 at 3:30 AM, Pavel Malyshev <email address hidden>
wrote:

> Just FYI:
> The bug, which Ubuntu cannot fix for 7 (SEVEN!!!) years, was fixed in
> Fedora in 1.5 months: https://bugzilla.redhat.com/show_bug.cgi?id=1141525
>
> ** Bug watch added: Red Hat Bugzilla #1141525
>    https://bugzilla.redhat.com/show_bug.cgi?id=1141525
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/207473
>
> Title:
>   Screen brightness double level changes on Dell laptops
>
> Status in Linux:
>   Fix Released
> Status in hal package in Ubuntu:
>   Invalid
> Status in kde-guidance package in Ubuntu:
>   Fix Released
> Status in linux package in Ubuntu:
>   Fix Released
> Status in hal source package in Hardy:
>   Invalid
> Status in kde-guidance source package in Hardy:
>   Fix Released
> Status in linux source package in Hardy:
>   Invalid
>
> Bug description:
>   Binary package hint: gnome-power-manager
>
>   I have a fresh installation of Hardy with the latest updates installed
>   on a Dell Inspiron 6400 laptop. The brightness settings (Fn+Up/Down)
>   work although they seem to skip a level each time.
>
>   '/proc/acpi/video/VID/LCD/brightness' tells me that it supports
>   brightness levels 12, 24, 36, 48, 60, 72, 84 and 100. Without gnome-
>   power-manager running pressing Fn+Up will transition up into each
>   level and back down again smoothly.
>
>   When gnome-power-manager is running increasing the brightness from 12
>   I can only get levels 36, 60, 84 and 100. Decreasing the levels from
>   100 I only get 72, 48, 24 and 12. Running gnome-power-manager with the
>   verbose option shows that when I press the brightness-up button once
>   it is recorded twice. I ran gnome-power-manager in a debugger thinking
>   it was a timing issue and it still happened.
>
>   I have included the output from pressing the brightness-up button
>   (Fn+Up) once below. This only happens when gnome-power-manager is
>   running and did not happen using Feisty. I have looked at the code and
>   I cannot see why the button event is triggered twice, I don't have any
>   experience of the code but if you can give me any ideas of where to
>   start I can try to look into this myself.
>
>   Thanks!
>
>
>   [hal_device_condition_cb] gpm-button.c:391 (00:11:48):
>  condition=ButtonPressed, details=brightness-up
>   [emit_button_pressed] gpm-button.c:335 (00:11:48):     emitting
> button-pressed : brightness-up
>   [button_pressed_cb] gpm-manager.c:999 (00:11:48):      Button press
> event type=brightness-up
>   [button_pressed_cb] gpm-srv-screensaver.c:167 (00:11:48):      Button
> press event type=brightness-up
>   [button_pressed_cb] gpm-backlight.c:563 (00:11:48):    Button press
> event type=brightness-up
>   [gpm_brightness_lcd_get_hw] gpm-brightness-lcd.c:116 (00:11:48):
>  GetBrightness returned level: 0
>   [gpm_brightness_lcd_set_hw] gpm-brightness-lcd.c:155 (00:11:48):
>  Setting 1 of 7
>   [gpm_brightness_lcd_up] gpm-brightness-lcd.c:362 (00:11:48):   emitting
> brightness-changed (14)
>   [brightness_changed_cb] gpm-backlight.c:755 (00:11:48):        Need to
> display backlight feedback value 14
>   [gpm_feedback_display_value] gpm-feedback-widget.c:144 (00:11:48):
>  Displaying 0.140000 on feedback widget
>   [gpm_refcount_add] gpm-refcount.c:100 (00:11:48):      refcount now: 1
>   [gpm_refcount_add] gpm-refcount.c:101 (00:11:48):      non zero, so
> sending REFCOUNT_ADDED
>   [brightness_changed_cb] gpm-backlight.c:759 (00:11:48):        emitting
> brightness-changed : 14
>   [button_pressed_cb] gpm-info.c:698 (00:11:48):         Button press
> event type=brightness-up
>   [hal_device_condition_cb] gpm-button.c:391 (00:11:48):
>  condition=ButtonPressed, details=brightness-up
>   [emit_button_pressed] gpm-button.c:335 (00:11:48):     emitting
> button-pressed : brightness-up
>   [button_pressed_cb] gpm-manager.c:999 (00:11:48):      Button press
> event type=brightness-up
>   [button_pressed_cb] gpm-srv-screensaver.c:167 (00:11:48):      Button
> press event type=brightness-up
>   [button_pressed_cb] gpm-backlight.c:563 (00:11:48):    Button press
> event type=brightness-up
>   [gpm_brightness_lcd_get_hw] gpm-brightness-lcd.c:116 (00:11:48):
>  GetBrightness returned level: 1
>   [gpm_brightness_lcd_set_hw] gpm-brightness-lcd.c:155 (00:11:48):
>  Setting 2 of 7
>   [gpm_brightness_lcd_up] gpm-brightness-lcd.c:362 (00:11:48):   emitting
> brightness-changed (28)
>   [brightness_changed_cb] gpm-backlight.c:755 (00:11:48):        Need to
> display backlight feedback value 28
>   [gpm_feedback_display_value] gpm-feedback-widget.c:144 (00:11:48):
>  Displaying 0.280000 on feedback widget
>   [gpm_refcount_add] gpm-refcount.c:100 (00:11:48):      refcount now: 2
>   [gpm_refcount_add] gpm-refcount.c:101 (00:11:48):      non zero, so
> sending REFCOUNT_ADDED
>   [brightness_changed_cb] gpm-backlight.c:759 (00:11:48):        emitting
> brightness-changed : 28
>   [button_pressed_cb] gpm-info.c:698 (00:11:48):         Button press
> event type=brightness-up
>   [gpm_refcount_auto_decrement] gpm-refcount.c:77 (00:11:50):    refcount
> now: 1
>   [gpm_refcount_auto_decrement] gpm-refcount.c:74 (00:11:50):    zero, so
> sending REFCOUNT_ZERO
>   [gpm_feedback_close_window] gpm-feedback-widget.c:134 (00:11:50):
> Closing feedback widget
>
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