Comment 44 for bug 1349740

Phew! It's been a long time since i last updated this report, and a lot of testing has happened but everything is at long last fixed.

First of all, i think i should say what an absolute mess the UEFI/Boot settings are in. I discovered that all these acpi problems, errors for the keyboard, hiccups with ehci not behaving and most importantly: the backlight not working despite reconfiguring it and the machine not powering off properly were all caused as a result of a faulty EFI install of ubuntu 14.10 and _i think_ some systemd-logind bug or at the least inherent to a package in ubuntu 14.10 rather than kernel-side.

When i gave up with 14.10 yesterday and installed 14.04 LTS, there isn't a single problem to be found anywhere; the difference in stability is astounding.

That patch you mentioned for me to try, according to that bug report, was ported upsteam into 3.18rc3 and i've been trying every kernel (both mainline debug and custom made with ehci support disabled etc) during the 3.18 cycle with varying amounts of success but never solving the power problems fully.

I looked into the UEFI settings and found a player in this crime - tried installing ubuntu in legacy and met with exactly all the same problems in this bug report, then tried manually creating EFI partition and switching back to UEFI (which caused LOTS of grey hairs!) which eventually worked but then didn't solve the problems anyway (black screen and random hangs at random unless modesetting was disabled) and there seemed to be underlying systemd errors. Booting successfully was like a 1 in 5 chance.

You'll notice that before in this bug report, i manually set systemd to take over with "init=/lib/systemd/systemd" as this has proven effective and harmless before with 14.04 installations - however, in ubuntu 14.10 by default the system has a bizarre mix of inits with systemd not-quite-in-charge-100% and i suspect it wasn't getting information from a daemon or understanding something. (I wish i hadn't just lost my last dmesg in that reinstall.)

Since october, i've tried a kernel from just about every main version 3.12-3.18rc5 and still met with teething pains over UEFI/Legacy boot and something else (bootloader related?). I'm quite fed up with how easy it is to upset it and will be sticking with ubuntu trusty on my friend's laptop for the foreseeable future.

In short:
installing ubuntu 14.10 + booting grub-pc (legacy) -> all these acpi problems and needed that patch now in 3.18rc3 just to boot; instability and won't poweroff
installing ubuntu 14.10 + booting grub-efi (EFI) -> ehci behaves itself but the screen is still fickle, if not more, so and loves to keep going black
install ubuntu 14.04 + booting grub-efi (EFI) -> no problems at all, even powers off at shutdown