Red Hat Bugzilla – Bug 451180
No display backlight when resuming eeepc from sleep
Last modified: 2015-03-04 20:19:54 EST
Description of problem: Resuming eeePC 701 from sleep, results in no
backlight... for getting light back, you need to press FN+F4 (backlight
controls) and brightness come back
Version-Release number of selected component (if applicable):
fedora 9 full updated
We got it working, with this workaround:
This works for the eeepc701. But doesn't work in eeepc901. In this last one, the
user must HARD RESET.... no way to resume backlight.
Display brightness resuming, without tweaks
Have you tried "pm-suspend --quirk-reset-brightness" ?
Tried now in my eeepc 701:
using pm-suspend --quirk-reset-brightness
at resume I have brightness at 125 % (it's brighter than usual maximum) , and I
can't change the brightness using Fn keys (they usually work directly, also
while loading OS)
It would be nice to test this command in eeepc 900/901, that can't resume with
the lamer workaround (reading value and setting it)
Why isn't the kernel using a standard brightness class?
Does xbacklight also change the brightness on this PC?
how to try it? can you tell what to do, to test it out?
ps gnome-power-management seems to not see the "brightness"..... I remember with
other distributions, it was able to change brightness...for example, with pc
xbacklight isn't shipped by default, it's available here:
This uses the X.org driver to set the brightness, and not any kernel bits. Try
it out in X, and see if it allows the brightness to change again after a resume.
I disabled my workaround (so, stock 99video)
suspended using: pm-suspend --quirk-reset-brightness
Resumed (brightness 125 %....)
xbacklight, gives me "100%" value
I setted with xbacklight, 50 %..... no change.... but xbacklight reports 50 %..
strange... it's like a "broken" link between hardware and software....
Now (rebooted) I tried:
stock 99video script
NORMAL SUSPEND (without --quirk-reset-brightness)
after resume (black screen....resumed pressinf Fn+F4)
xbacklight: 100 %
xbacklight -set 50 ........worked faded to 50 % brightness.
so: with stock fedora, and pressing fn+f4 , xbacklight WORKS.
using quirk-reset-brightness, xbacklight doesn't work.
GREAT, kernel-2.6.26-0.67.rc6.git1 FIXES THIS PROBLEM!
I tried, and backlight is correctly resumed.
After, I tried the "stable" kernel, and backlight doesn't work (obviously) with
it. So kernel 2.6.26 has a working resume from suspend for brightness.
Let's wait this kernel, it takes fresh air to my netbook :)