[ubuntu] Sony E series brightness control not working in 12.10

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http://ubuntuforums.org – I have a Sony E series laptop (64 bit) where keys Fn+F5 and Fn+F6 should control the screen brightness. On my machine these keys do control the brightness "slider", but they do not control the actual screen brightness. I am running Ubuntu 12.10. These keys did work to control screen brightness when running Ubuntu 12.04 LTS, but I updated to 12.10 to get EFI boot working correctly. To date I have tried various kernel bootup options to get the keys working, but none have proved effective. I have tried; acpi_backlight=video acpi_backlight=vendor acpi_osi=Linux acpi_osi=Linux acpi_backl (Hardware)