Arch Linux

glenb77

Member

Registered: 2014-10-02

Posts: 68

backlight off after upgrade

on an asus x200ma after upgrade today the backlight is completely off. i have the system set up to just boot to a console login and then i use startx to go to gnome. when it boots i see the normal items and then it goes off. if i blindly enter my login and password, and then suspend the machine, when it wakes up there is video. if i blindly hit startx i can tell from hd led that it runs gnome but again no video.

this is not an issue where the backlight brightness is not being set. if i simply boot and then ssh in from another computer i can see in my sys/class/backlight/intel_backlight that my brightness level is correct and what it always was. i have tried masking the save backlight service, nothing changed. it seems like the power is being cut off, but whatever it is, the resume commands restore the video. from the ssh session on another computer the values in the intel backlight dir are the same whether the screen is actually on or not. i have no other directory under /sys/class/backlight and once on, changing the brightness value will work as well as changing the brightness icon from within gnome (x server).

i appreciate any help i can get with this.

nadley

Member

Registered: 2014-09-01

Posts: 7

Re: backlight off after upgrade

I can't be of much help, but I also have a Asus X200MA and can confirm that the screen is totally black after upgrading to kernel 3.18.4. 3.18.5 also has the same problem.

When downgrading the kernel to 3.18.3 or 3.17.6, the backlight works (but not the backlight buttons). I have tried most things described on the arch backlight wiki page, but nothing seems to help.

paulkerry

Member

From: Sheffield, UK

Registered: 2014-10-02

Posts: 611

Re: backlight off after upgrade

I also had this on a HP ProBook 450 laptop. On booting, the backlight was on until kdm started at the end of the boot process, at which point the screen went totally black.
At this point, I could ctrl-alt-f1 to get to a tty login at which point the backlight came on: from there, I could login as root and restart kdm and immediately kdm started with the backlight on again.

I'm unsure if it helped or not, but I reinstalled the kernel again (I'm using the regular linux version) and since then everything has worked perfectly!

Cheers
Paul.