backlight on Lenovo 3000 C200 can't be set to maximum again
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
Ubuntu |
Invalid
|
Undecided
|
Unassigned |
Bug Description
I've got a very strange problem on a Lenovo 3000 C200 notebook. When I first started Ubuntu after the installation the backlight of the screen is "normal" as it was on the preinstalled Windows. But after I decreased the Brightness via the fn + brightness dimming keys, it can't be set to maximum again. I assume there are five different brightness levels. Let's call the normal one 5. Then I decrease to 4. Afterwards I can't increase to 5 again. But I can decrease to 3. Afterwards I can't increase to 4 oder 5 again. But I can switch between 1, 2 and 3 without problems. I'm just not able to get to 4 or 5 again. When I try to adjust the brightness before Ubuntu boots, for example in the grub menu, I can go to 5 again. But after Ubuntu takes the control it falls back to level 3.
I can confirm this issue on another C200. Only a reboot allows to access the brightest levels again. (At the grub prompt increasing the brightness is still working.)