Comment 117 for bug 1169376

@Francisco and others,

Please check here for the latest status on what's going on upstream:

https://bugzilla.kernel.org/show_bug.cgi?id=47941

Some users have popped out of the woodwork to declare that the most recent patches that went in *breaks* the backlight completely (black screen on boot) for one particular XPS13 configuration: IvyBridge with UEFI enabled
along with Legacy BIOS enabled. (Those same users also say that backlight control *always* worked for them, even without _any_ patch).

To complicate things further, a couple of other users with the same UEFI +Legacy configuration say the exact opposite: That the quirk patch fixes their never-before-working backlight control (same as for all the other non-UEFI users).

If anyone with an affected machine is willing to pitch in and help with the latest patches being worked on please do so.