Public bug reported:
SInce the upgrade to Ubuntu 12.10, hardware keys for regulating
backlight brightness (fn+f4, fn+f5) change brightness in large
increments, even though much finer control is available both through the
Brightness and Lock dialog in Settings and by just setting the value in
/sys/class/backlight/acpi_video0/brightness, for example:
# echo 1 > /sys/class/backlight/acpi_video0/brightness
/sys/class/backlight/acpi_video0/brightness accepts values 0-15, the
default step seems to be 3 instead of 1 as expected, and as it was in
Ubuntu 12.04.
Partial workaround is to disable brightness switch
# echo -n 0 > /sys/module/video/parameters/brightness_switch_enabled
which cuts the step to 2. Moreover, adding kernel parameters
"acpi_osi=Linux acpi_backlight=legacy" allows for even finer control in
the Brightness and Lock dialog in Settings (finer than those 16
settings, including completely turning the backlight via the brightness
slider) but breaks the hardware keys functionality completely.
# lsb_release -rd
Description: Ubuntu 12.10
Release: 12.10
** Affects: linux (Ubuntu)
Importance: Undecided
Status: Incomplete
** Tags: quantal regression-release
** Description changed:
SInce the upgrade to Ubuntu 12.10, hardware keys for regulating
backlight brightness (fn+f4, fn+f5) change brightness in large
increments, even though much finer control is available both through the
Brightness and Lock dialog in Settings and by just setting the value in
/sys/class/backlight/acpi_video0/brightness, for example:
# echo 1 > /sys/class/backlight/acpi_video0/brightness
/sys/class/backlight/acpi_video0/brightness accepts values 0-15, the
default step seems to be 3 instead of 1 as expected, and as it was in
Ubuntu 12.04.
Partial workaround is to disable brightness switch
# echo -n 0 > /sys/module/video/parameters/brightness_switch_enabled
which cuts the step to 2. Moreover, adding kernel parameters
"acpi_osi=Linux acpi_backlight=legacy" allows for even finer control in
the Brightness and Lock dialog in Settings (finer than those 16
- settings, backlight including completely turning the backlight via the
- brightness slider) but breaks the hardware keys functionality
- completely.
-
+ settings, including completely turning the backlight via the brightness
+ slider) but breaks the hardware keys functionality completely.
# lsb_release -rd
Description: Ubuntu 12.10
Release: 12.10
--
You received this bug notification because you are a member of Ubuntu-X,
which is subscribed to xorg in Ubuntu.
https://bugs.launchpad.net/bugs/1069357
Title:
Hardware keys change backlight brightness in much larger
increments/steps than expected
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1069357/+subscriptions
_______________________________________________
Mailing list: https://launchpad.net/~ubuntu-x-swat
Post to : ubuntu-x-swat@lists.launchpad.net
Unsubscribe : https://launchpad.net/~ubuntu-x-swat
More help : https://help.launchpad.net/ListHelp
