[SOLVED] [LM19 MATE] Backlight Setting Resets

[WISEGUYTR]

Just installed clean LM19MATE.

The background lights keep on forgetting it's setting after each reboot and suspend/wakeup. I have to manually open the Power Manager and click on the percentage bar to make it "remember". As a quick workaround I added the LCD Brightness applet to the command bar, but the problem still exists.

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System:   Host: MATE Kernel: 4.15.0-32-generic x86_64 bits: 64
              Desktop: MATE 1.20.1  Distro: Linux Mint 19 Tara
Machine: Device: laptop System: Hewlett-Packard product: HP ProBook 4530s v: A0001D02 serial: N/A
              Mobo: Hewlett-Packard model: 167C v: KBC Version 22.26 serial: N/A
              BIOS: Hewlett-Packard v: 68SRR Ver. F.63 date: 04/06/2017
Battery   BAT0: charge: 38.7 Wh 100.0% condition: 38.7/38.7 Wh (100%)
CPU:       Dual core Intel Core i5-2450M (-MT-MCP-) cache: 3072 KB
              clock speeds: max: 3100 MHz 1: 810 MHz 2: 805 MHz 3: 817 MHz
              4: 852 MHz
Graphics:Card: Intel 2nd Generation Core Integrated Graphics Controller
              Display Server: x11 (X.Org 1.19.6 ) driver: intel
              Resolution: 1366x768@60.03hz
              OpenGL: renderer: Mesa DRI Intel Sandybridge Mobile
              version: 3.3 Mesa 18.0.5

[gm10]

Run this (it likely won't produce any output):

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sudo chown -R $USER:$USER $HOME

Log out and back in or reboot to see if that fixed it.

[WISEGUYTR]

Run this (it likely won't produce any output):

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sudo chown -R $USER:$USER $HOME

Log out and back in or reboot to see if that fixed it.

Tried it, but when it wakes up from suspend, it's the same. The brightness sets to max.

[gm10]

Hmm, no idea why it wouldn't save then. You could script it to be set automatically I guess.

Set your brightness to what you want it to be. Then run this

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P=/sys/class/backlight/*/brightness;find $P;cat $P

It should output exactly one path and one number. If it outputs anything else then post the output and don't continue with the next step.

Otherwise run this:

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P=/sys/class/backlight/*/brightness;T=/etc/rc.local;printf "echo $(cat $P) > $(find $P)\n"|sudo tee $T;sudo chmod +x $T

Reboot and see if it works on boot. If it does we'll also script it upon resume.

[WISEGUYTR]

It actually saves it, but for some reason it forgets to check it after suspend. I mean when I look at the Power Settings, I see that it is in the set position after wake up from suspend. When I click on the bar to tune the brightness, it suddenly "remembers it".

I am wondering if there's some other place to set the brightness than this one.

[WISEGUYTR]

Hmm, no idea why it wouldn't save then. You could script it to be set automatically I guess.

Set your brightness to what you want it to be. Then run this

Code: Select all

P=/sys/class/backlight/*/brightness;find $P;cat $P

It should output exactly one path and one number. If it outputs anything else then post the output and don't continue with the next step.

Otherwise run this:

Code: Select all

P=/sys/class/backlight/*/brightness;T=/etc/rc.local;printf "echo $(cat $P) > $(find $P)\n"|sudo tee $T;sudo chmod +x $T

Reboot and see if it works on boot. If it does we'll also script it upon resume.

The results I get are :

/sys/class/backlight/acpi_video0/brightness
/sys/class/backlight/intel_backlight/brightness
20
168


[gm10]

Ah, one of those situations. Can you try the following, run this from a terminal:

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xed admin:///etc/default/grub

In the editor that pops up, authenticate then find the GRUB_CMDLINE_LINUX_DEFAULT line and add acpi_backlight=none so that it looks something like this

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GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=none"

(and potentially more parameters if you had already added your own)

Save the file, run

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sudo update-grub

and after a reboot your backlight might work correctly. It's also possible you'll lose backlight control completely though. Let me know.

[WISEGUYTR]

Ah, one of those situations. Can you try the following, run this from a terminal:

Code: Select all

xed admin:///etc/default/grub

In the editor that pops up, authenticate then find the GRUB_CMDLINE_LINUX_DEFAULT line and add acpi_backlight=none so that it looks something like this

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GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=none"

(and potentially more parameters if you had already added your own)

Save the file, run

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sudo update-grub

and after a reboot your backlight might work correctly. It's also possible you'll lose backlight control completely though. Let me know.

OM(F)G....I dont believe it ! After searching for a solution for over 2 months, you seem to have found the solution.! Thank you so much for your help !

Now my grub line looks like:

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GRUB_CMDLINE_LINUX_DEFAULT="elevator=deadline quiet splash video.use_native_backlight=0 acpi_backlight=none"

[gm10]

OM(F)G....I dont believe it ! After searching for a solution for over 2 months, you seem to have found the solution.! Thank you so much for your help !

Glad to hear that, you are quite welcome.

[justletitgo4ever]

OM(F)G....I dont believe it ! After searching for a solution for over 2 months, you seem to have found the solution.! Thank you so much for your help !

Glad to hear that, you are quite welcome.

Hi gm10,

I have exact the same problem, after reboot and resume from sleep, backlight always reset to max. I follow the above instruction you given, but still not working for both reboot and resume. I am using LM 19 XFCE though. What else should I try? Thanks and happy new year!