I looked into the screen brightness issue a little bit a while back. The reason that the brightness gets set to maximum at boot is that the firmware doesn't initialize some state memory with the brightness at boot, so when the brightness is read from the firmware it gets back a value which corresponds to the maximum brightness. When Linux boots the acpi_video driver does some tests of various functionality which includes reading the current brightness and writing it back, which has the effect of setting the screen brightness to maximum.
What OS X seems to do is to write the screen brightness to an EFI variable, so either acpi_video would need to know to look for that variable or else acpi_video just shouldn't be used for brightness on Apple hardware. As a workaround you could pass acpi_backlight=vendor on the kernel command line to disable use of the ACPI backlight interface. Not sure about the keyboard backlight, but it could be something similar. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1279308 Title: [MacBook Air 6,2] screen backlight brightness and keyboard light turn into fully-on after Grub boot with i915 driver To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1279308/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
