Comment 1 for bug 333386
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| unclben (red117+launchpad) wrote Re: Cannot change brightness with 2.6.27-11+ kernel | #1 |
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I can confirm this on my ThinkPad (dmidecode outputs below).
Lenovo
7668CTO
ThinkPad X61s
The laptop is only a few days old. When running the Intrepid Live CD (which I assume is an older kernel than 2.6.27-11), backlight control worked fine. Since installing and updating to current kernel, however, I cannot control the backlight level at all. I have tried the function keys, the gnome brightness applet, and the xbacklight CLI application.
It seems that whatever brightness I set in the power management settings GUI takes effect when I boot fresh (i.e. full boot, not a resume from suspend or hibernate). xbacklight also reports that setting.
If I try to change the setting via the function keys, the OSD appears and the bar will move as it should... but the backlight doesn't actually adjust. If I try to change via the brightness applet slider, it moves up and down and holds position... but the backlight doesn't actually adjust. If I try to set a new level via xbacklight -set XX, xbacklight -get will report the value that I set (well, it's actually off by a smidge, but by and large it's the same number)... but the backlight doesn't actually adjust.
Is there anything else I can provide to help debugging?
Aside from the obvious battery life concern, having the wrong LCD backlight level for the current ambient lighting condition can be a huge eyestrain and can even render the laptop unusable in some cases. (this is my pleading to avoid getting set at 'low' importance)