Xfce Forum

Sub domains
 

You are not logged in.

#1 2017-11-07 14:52:37

am4c130d
Member
Registered: 2014-01-07
Posts: 8

[SOLVED] Screen brightness not reset on resume from suspend/hibernate

Hi all

I'm looking for some help with a slight strange, and somewhat annoying issue I am having with the display brightness on my laptop screen when the laptop resumes from suspend or hibernate. My system is:

XFCE 4.12
Power Manager 1.4.4
systemd 235-2
Debian Buster/sid
Lightdm 1.18.3-4
lightlocker 1.0.8-1
HP 8440p with an external monitor (I use both screens in an extended setup).

My laptop suspends/hibernates perfectly with the exception that the screen brightness on the laptop display is reduced to 5% when it resumes.  xfce4-power-manager is set to manage the display:

On battery
Blank: 5 mins
Sleep: 10 mins
Switch off: 15 mins
Brightness reduction: 20%
After: 120 seconds

Plugged in
Blank: 5 mins
Sleep: 10 mins
Switch off: 15 mins
Brightness reduction: 80%
After: Never

/etc/logind.conf is default, except HandlePowerKey is set to suspend.

Everything was working fine until I loaded Enlightenment DE, which I've since purged from the system and I cannot find what change was made that sets the brightness during idle/sleep but doesn't allow it to recover.

I can increase the display brightness using the laptop keyboard FN keys, the XFCE4-power-manager icon in the systray and by directly changing /sys/class/backlight/intel_backlight/brightness

I've reinstalled xfce4-power-manager etc. all to no avail.

Its annoying, as opposed to a real issue, but I'd like to address it, if possible. Any helps appreciated - thanks.

Alan

Last edited by am4c130d (2017-11-09 20:43:39)

Offline

#2 2017-11-07 17:39:15

ToZ
Moderator
From: Canada
Registered: 2011-06-02
Posts: 3,869

Re: [SOLVED] Screen brightness not reset on resume from suspend/hibernate

When you installed enlightenment, did you install all the recommended dependencies as well? I notice from the package file that pm-utils is a recommended dependency and it has some hooks that might affect system configuration on resume from suspend.

I'm not sure if pm-utils is part of the base sid install or whether its required, but if it was installed as a dependency of enlightenment, trying removing it.


How To Ask For Help           Xfce FAQ                            Xfce Release Information
The Xfce Community          Xfce Tips and Tricks

Offline

#3 2017-11-08 17:41:54

am4c130d
Member
Registered: 2014-01-07
Posts: 8

Re: [SOLVED] Screen brightness not reset on resume from suspend/hibernate

Thanks ToZ.

pm-utils was installed - but not by Enlightenment, based on the other apps that seem to have been dependent/recommended at the same time. I should have added, I installed Enlightenment from experimental as Sid has a really old version. However, I did remove pm-utils, and rebooted - no joy unfortunately.

Observing things more closely, the laptop screen resumes at full brightness and then instantly drops to 5% - not sure if that is useful info. I'll look at the various suspend/sleep scripts in case there is a conflict there as well.

Thanks

Offline

#4 2017-11-08 18:21:51

ToZ
Moderator
From: Canada
Registered: 2011-06-02
Posts: 3,869

Re: [SOLVED] Screen brightness not reset on resume from suspend/hibernate

What about TLP or  laptop mode tools? Both also have capabilities to dim the screen based on configured settings.


How To Ask For Help           Xfce FAQ                            Xfce Release Information
The Xfce Community          Xfce Tips and Tricks

Offline

#5 2017-11-08 21:54:41

am4c130d
Member
Registered: 2014-01-07
Posts: 8

Re: [SOLVED] Screen brightness not reset on resume from suspend/hibernate

Thanks for sticking at this, greatly appreciated: neither of those packages are loaded. I scrubbed out acpid, acpi and acpi-support-base as well, just in case. It looks like its just xcfe4-power-manager, upower, powermgmt-base and systemd are installed now that control power.

I thought I'd made some progress, but I'm not sure.

systemd-backlight@backlight:intel_backlight.service appears to control what happens. However, it doesn't appear to launch the execstart command when the system resumes from suspend - I suspect because it already running. Its "config" file

/var/lib/systemd/backlight/pci-0000:00:02.0:backlight:intel_backlight 

appears to retain the correct value across suspends, and manually issuing

/lib/systemd/systemd-backlight load backlight:intel_backlight 

which is the execstart command restores the backlight value - but

systemctl start systemd-backlight@backlight:intel_backlight.service 

does not, as it doesn't reissue the systemd-backlight load command.

The man page for systemd-backlight talks about clamping the brightness to 1 or 5% of max, until some user space process can safely set it. The brightness is set to 36 on my system on resume, which is 5% of maximum. So it feels to be in this area that the issue lies - but I haven't worked out what needs to happen to restore it under the control of systemd. The variable referenced in the man page ID_BACKLIGHT_CLAMP is not configured in my udev scripts - and that seems unlikely to have changed.

I don't have this issue when I reboot - everything comes up correctly. I haven't investigated the suspend scripts yet...

Any thoughts?

Offline

#6 2017-11-09 20:42:56

am4c130d
Member
Registered: 2014-01-07
Posts: 8

Re: [SOLVED] Screen brightness not reset on resume from suspend/hibernate

SOLVED!

/sys/class/backlignt/acpi_video0/actual_brightness 

and

/sys/class/backlignt/acpi_video0/brightness 

Were both set to 1.  Whereas

/sys/class/backlignt/acpi_video0/max_brightness 

Had a value of 24, and

/sys/class/backlight/intel_backlight/actual_brightness
/sys/class/backlight/intel_backlight/brightness
/sys/class/backlight/intel_backlight/max_brightness 

were all 684 - i.e. maximum.

Setting

/sys/class/backlignt/acpi_video0/brightness 

to 24 fixed it! actual_brightness followed suit automatically.

I'm guess the kernel on resume reads acpi_video0, whereas systemd and xfce4_power_manager both read and set intel_backlight - they appear to be the generic and vendor specific settings for the same card.

Offline

Board footer

Powered by FluxBB