According to Yung's comment on #3, the "Windows 2012" means "Windows 8 and Server 2012" The linux kernel will tell the BIOS we are Win8 after kernel 3.7, the kernel parameter in #3 tells the BIOS that we are Win7. So, it looks like it's a BIOS issue that has different behavior on Win7 and Win8.
We can try to use the newer version of BIOS to see if it can fix this issue. Other solutions are all workarounds. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1270079 Title: [Lenovo T540p, W540] Backlight interfaces not fully working To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-lts-raring/+bug/1270079/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
