10.04 was just a piece of cake. I almost forgot these gradient buttons. Today they look a bit clumsy but back then I was pretty neat. I really missed them in 11+. But most importantly it doesn't mess up my backlight. I wonder what happened between 10 and 12. The suspects are systemd with it's backlight daemon and unspecified kernel options. I guess there is only one way to understand: I need a system without systemd

Bad news: it's not Systemd. And it's not ACPI either (acpi=off gives the same result + non-functional wifi as a bonus). Time to read a kernel config diffs. But first I want to check out if earlier builds of 12.04 work (and maybe 14.04 too)

12.04.0 works fine. Wow. Next step is 14.04.0. Was it 16.04 when it stopped working?

14.04.0 doesn't work. At least I don't have to check every version up to 16.04. Anyway, I always have FreeBSD as an alternative

13.10 doesn't work either. I wish there was a different way, other than a damn brutforce

13.04 is broken too. Only one version to go

I think I've found the exact bugfix that broke my backlight. And if I'm right 12.04.1 won't work. But first, testing 12.10. bugs.launchpad.net/ubuntu/+sou

I was wrong. 12.04.1 works fine. Moreover 12.04.2 is fine too. And it uses the same kernel version as 13.04 (3.5.0-17 vs 3.5.0-23). Diff shows not so many changes:

* usb otg unset
* amd_iommu_v2 added as module (virtualization)
* drm_i915_hsw added as module (intel graphics driver)

It's time to build the kernel, I guess

Blacklisting these modules didn't do much. I've even had an idea that it might be acer_wmi, but it's not. It couldn't be otg, could it? And happiness was so damn close...

I feel like an idiot. Wrong version, wrong config, wrong diff. Everything is wrong. Need more 12.04 tests

12.04.3 is broken. It uses 3.8.* branch of kernel, the same as 13.04. Something happened between 3.5 and 3.8. The problem is official kernels of these versions mysteriously disappeared from the wild and there no ubuntu distros with them. But I see the links to mainline ppa everywhere. :AAAAAA:

I give up. I'm reading the kernel's change logs starting with 3.6 and sloooowly downloading . I hope the fixed an installer (they said it works already)

This is weird. GhostBSD failed too. And what am I supposed to do? At least this means they have a common 3rd party driver or the one that is broken the same way.

It's 3:30 am and my condition is close to a raging potato.


Patient: Acer Aspire 5742G
Age: 10yo
CPU: Intel Core i3 380M
Video: AMD 6370M/radeon (replaced)
Symptoms: backlight brightness level is being dropped to the lowest after every reboot starting with linux kernel between 3.6 and 3.8.
Diagnosis: backlight or video driver malfunction.

Which one is broken? This is the question

@replikvlt Yep. Is is not the only option I tried. The problem is that backlight is being dropped down not on load but on shutdown. I mean the display is dim even at the bios screen

@replikvlt this is not: ubuntu before 13.04 and windows 7 work fine

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