The keyboard backlight issue is separate from this issue, and is not a
hardware problem.

Rather, that the linux devs decided to disable the samsung-laptop.c module in 
the kernel when you boot with UEFI, as a preventive measure when it still 
wasn't clear how linux interacted with that famous samsung uefi bug.
Looking in:

         http://lxr.free-electrons.com/source/drivers/platform/x86
/samsung-laptop.c

I see that the following lines prevent the module from being initialized
when you use UEFI, and so keyboard backlighting isn't enabled:

             1548         if (efi_enabled(EFI_BOOT))
             1549                 return -ENODEV;

If those two lines were introduced as a preventive measure or as a real
fix for the famous samsung UEFI bug, I don't know. I have a series 5
NP530U3C which doesn't have backlighting. DO NOT uncomment those lines
and recompile the kernel, unless some expert on that old famous UEFI bug
says its ok to do so.

But again, it is a separate issue and it's clear that the lack of
keyboard backlighting is a software thing and not related to the bugs
fixed here by my workaround, by unblocking the EC embedded controller.


The workaround fix I posted in posts #101 through #103 fixes the "problem 
state" that the laptop gets into from a "bad" suspend/resume, in which LID 
close events are not generated, and AC plugged in status is ignored, and 
battery charge changed events are not generated (and maybe some temperature 
alert / changed issues too). And of which one could only got out by hitting the 
reset button through the hole in the back while turned off.

Cheers!
--
Juan Manuel Cabo

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https://bugs.launchpad.net/bugs/971061

Title:
  acpi reports battery state incorrectly

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