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I have no remembrance of having done anything but now my ubuntu 12.04 always boots with very low screen brightness. I can then adjust it with FN+Pos1. I have a Lenovo X220.

Neither xbacklight nor any setting in the system settings has any effect. I did read some recommendations about complicated python scripts.

But why? I did not change anything! Why is ubuntu broken?

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Maybe something has been updated. Please [](paste) the output from the file /var/log/apt/history.log, and also the output from lshw -c display to know something about your graphics hardware. – Jorge Suárez de Lis Feb 7 '13 at 0:21

issue is solved.

weird fact: some SETTING in the Lenovo Energy Program which comes with Windows 7 was set to "reduce screen brightness during boot and shutdown". I did again switch off this setting and this solves my issue in LINUX!

how can this be? how can windows settings have the same effect in ubuntu? some ACPI BIOS setting?

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