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-   -   After replacing thinkpad screen, brightness control stopped working (http://www.linuxquestions.org/questions/linux-laptop-and-netbook-25/after-replacing-thinkpad-screen-brightness-control-stopped-working-4175445443/)

erraph 01-13-2013 04:25 PM

After replacing thinkpad screen, brightness control stopped working
 
Good evening!

Good to be here. I replaced the screen of my Thinkpad edge 13, after it suffered for more than 6 month from the well-known central vertical lines-problem...
With the new screen, the brightness control via FN-F7/F8 stopped working.
Even manually it's not possible to set the brightness.

Code:

ls /sys/class/backlight/*/brightness
/sys/class/backlight/intel_backlight/brightness
/sys/class/backlight/thinkpad_screen/brightness

where max_brightness equals 4422465 (!) for the first and 15 for the second.
FN-F7/F8 writes to thinkpad_screen/brightness, but also echo'ing numbers from the interval [0 - 4422465] to intel_backlight/brightness can only turn on and off the backlight, but not dim it.

I changed
Code:

GRUB_CMDLINE_LINUX_DEFAULT="quiet acpi_backlight=vendor"
and ran update-grub. Didn't help.

Do you have some ideas how I could rule out hardware problems?
Would be great to get some pieces of advice!
Raphael


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