[SOLVED] Brightness control does nothing on Samsung NP470R5E

[Ramesez]

The screen brightness is stuck at 100%, not matter what I do.

The laptop is a Samsung NP470R5E.

Code: Select all

inxi -G
Graphics:
  Device-1: Intel 3rd Gen Core processor Graphics driver: i915 v: kernel 
  Display: x11 server: X.Org 1.20.13 driver: modesetting 
  unloaded: fbdev,vesa resolution: 1366x768~60Hz 
  OpenGL: renderer: Mesa DRI Intel HD Graphics 4000 (IVB GT2) 
  v: 4.2 Mesa 21.0.3 

Code: Select all

hostnamectl
Operating System: Linux Mint 20.2
            Kernel: Linux 5.4.0-94-generic
      Architecture: x86-64

I really need the brightness to be able to adjust, or else I will be stuck with windows 10 (which I hate immensely).

[HAWR]

Hello Ramesez,

I've just supported in two thread with brightness control problems, and both are solved. So I think, you can also find a solution within these threads. Have a try and report back:

viewtopic.php?f=49&t=365348

viewtopic.php?f=59&t=365008

[Ramesez]

https://www.debugpoint.com/2016/10/2-wa ... ntu-linux/

"Method 1: Fix Brightness Enabling Laptop Specific Drivers

Open the file /etc/default/grub using gedit or any other text editor.
Find the below line."
HOW THE HELL DO YOU DO THIS?

[HAWR]

Hello Ramesez,

it has nothing to do with hell but it could have been, that you know how to do it. Please open the terminal and run the following command:

Code: Select all

sudo -H xed /etc/default/grub

The text editor xed opens the grub file. Go to the line with

Code: Select all

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

and change it into

Code: Select all

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"

Then save and close the grub file. Back in terminal run

Code: Select all

sudo update-grub

reboot and see, if it helps with the brightness control. If it doesn't help, open again the grub file and change acpi_backlight=vendor in acpi_backlight=video. Save & close, sudo update-grub, reboot and see, if it works.

It both methods do not work, open the grub file again and change back into

Code: Select all

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

with the same procedure as before. Then please show in your next post your system informations

Code: Select all

inxi -Fxxxrz

Good luck!

[Ramesez]

Holy crap, that worked. (acpi_backlight=video)

Now, I have another question. Mint works fast on the live (USB) version, but things load slower after installation to the hard drive. Win 10 works fast on the HD that it's installed on. I am wondering, could the reason for the reduced speed be due to the hard drive speed? (5,400 RPM)

[HAWR]

Hello Ramesez,

I'm happy that we found a solution for your brightness control problem

I know the experience with different speeds between USB live system or the installation on (older) HDD, and you are right, that the difference lays in the hard drive speed. I assume that you have a dual boot with Windows on your laptop, right? Windows has a feature called "Fast Startup" and because of that, especially the boot of Windows goes faster. Windows don't really shut down because of that "Fast Startup" and therfore is faster on again. In a dual boot "Fast Startup" often causes problems on the Linux side like not working hardware devices. Or you can't access the Windows partition from Linux. If "Fast Startup" is disabled, Windows don't boot so quickly anymore and you can compare it better with LM. But I don't want to speculate too much, what exactly causes your experience, so please show your system informations and describe a little bit more in detail, where you see the differences:

Code: Select all

inxi -Fxxxrz

I searched in the Linux Hardware Database for your laptop model, but unfortunately it isn't listed there. If you want, you can probe your laptop for it as I have done woth my devices. You find the program in the software manager as "hw-probe" and the command for the terminal to probe your laptop. At the end you get a website link (URL) for your laptop.

https://linux-hardware.org

[Drugwash]

I really need the brightness to be able to adjust, or else I will be stuck with windows 10

If by chance your Mint uses the Cinnamon DE you can try the Applet PYE applet.

[HAWR]

Hello drugwash,

the brightness control problem is solved:

Holy crap, that worked. (acpi_backlight=video)

[Drugwash]

Yeah, saw that but thought maybe the user wants something at par with the Windows version, if not higher. If changing brightness is a big issue then maybe an automatic tool could save time and effort.
My notebook's brightness doesn't work either, can't remember the last time it did - maybe it's the kernel, maybe the driver, maybe some update - but the applet I made beats that simple function.

Anyway, it'd be a pity to miss it in case it's of use to someone. If Github weren't that anal in regard to logging in, and it weren't M$'s property I would've uploaded it to the Spices library.

[Ramesez]

Hello Ramesez,

I'm happy that we found a solution for your brightness control problem

I know the experience with different speeds between USB live system or the installation on (older) HDD, and you are right, that the difference lays in the hard drive speed. I assume that you have a dual boot with Windows on your laptop, right? Windows has a feature called "Fast Startup" and because of that, especially the boot of Windows goes faster. Windows don't really shut down because of that "Fast Startup" and therfore is faster on again. In a dual boot "Fast Startup" often causes problems on the Linux side like not working hardware devices. Or you can't access the Windows partition from Linux. If "Fast Startup" is disabled, Windows don't boot so quickly anymore and you can compare it better with LM. But I don't want to speculate too much, what exactly causes your experience, so please show your system informations and describe a little bit more in detail, where you see the differences:

Code: Select all

inxi -Fxxxrz

I searched in the Linux Hardware Database for your laptop model, but unfortunately it isn't listed there. If you want, you can probe your laptop for it as I have done woth my devices. You find the program in the software manager as "hw-probe" and the command for the terminal to probe your laptop. At the end you get a website link (URL) for your laptop.

https://linux-hardware.org

I dual boot linux and windows on my primary laptop, however, with this one I have them installed on separate hard drives and switch between them manually. I vehemently despise windows 10, as it is an utter abomination of an operating system. I wouldn't be using it at all, if it weren't for the screen brightness and speed issues.
To clarify about Linux loading slower, I mean that after it boots I will click to open the web browser and be left waiting 10+ seconds for it to appear. There is also a slight delay when I open the menu, or do any other task for the first time, that session. After I've opened the browser or the menu once, it will open next time at (about) normal speed. I recall it being more responsive on the live version, before the install. If it is indeed because of the HD, then I will order a better one and reinstall linux. I would install over Windows, but I fear I may need it in the future.

[HAWR]

Hello Ramesez,

I will click to open the web browser and be left waiting 10+ seconds for it to appear. There is also a slight delay when I open the menu, or do any other task for the first time, that session. After I've opened the browser or the menu once, it will open next time at (about) normal speed.

That's the normal behaviour with a spinning HDD. Once started, they are preloaded for following starts in that session. If you want it faster, take a SSD and not only programs start faster but also the boot is it. What HD's are in your Samsung Laptop?

Code: Select all

inxi -Dxxxz

[SMG]

Moderator note: Ramesez's secure boot violation issue has been moved to a more appropriate location and can now be found here.