Score:0

2017 Imac screen brightness after installing Ubuntu 20.4

jp flag

I have just installed (July 2021) Ubuntu 64 bit 20.4 on a 2017 Intel iMac

The sound was a problem, I have resolved that.

The Screen brightness is also a problem. I can not adjust the screen brightness using the Ubuntu software

I have little to no understanding of Ubuntu and command line instructions so will need to be led.

Anyone out there can spare some time to get the problem resolved?

darth_epoxy avatar
nl flag
Sorry tto say it but you might get better mac information from this https://github.com/Dunedan/mbp-2016-linux/issues/112 forum. You need the Mac firmware and will need to copy some files. There is no simple fix IMHO.
anzacpi avatar
jp flag
It certainly seems that there is no simple answer. Thank you
us flag
Does this work? https://askubuntu.com/questions/1295423/ubuntu-20-04-on-imac-mid-2011-cant-adjust-brightness
Score:0
ro flag

This is a normal Intel-Board inside?

I had the problem on my Intel-laptop and used this command as root (sudo -i):

echo 400 > /sys/class/backlight/intel_backlight/brightness

First try to find the path to the backlight-file and then try to change the backlight brightness. First reduce the number, so that you can still see something. If the screen is black (echo 0 > /sys/class/backlight/intel_backlight/brightness), then you can not see something any more.

You can start with 1000 and then go down and decrease 100 every time, till you can see some changes.

anzacpi avatar
jp flag
I dont understand what you want me to do. As I said I have little experience with command line instructions and prefer not to stuff it up completely
MikroPower avatar
ro flag
You don't have to. Simply take a look at your Linux "explorer" ... the file-browser. In my case it is called Nautulus. Go to your root "/" and then to "/sys" ... till you seethe file "brightness". This path: /sys/class/backlight/intel_backlight/brightness Does it exist?
anzacpi avatar
jp flag
I found Nautilus and am unable to find out how to go to "Root" I took a desktop photo of what I have with the expectation that I could share that with you to give me some insight into where to go to next. Sorry to be so bloody slow but its al new to me
MikroPower avatar
ro flag
This is okay, I had to figure out how it works too. Press in your filebrowser (natilus, thunar or what ever is installed on your system) "Strg + L" and then you can insert a path. Maybe "/" (= root of the system) or "/sys/class/" then you can see ... is there a folder named backlight or something what looks like the name could be related to the background light and then go into the folder and look further ... is there a folder "intel_backlight" or something similar. If this would be true, then try the command in your terminal (in Windows you would start "cmd").
anzacpi avatar
jp flag
Thank you. I will explore what you are telling me there and see if I can get the working.. I appreciate your help
anzacpi avatar
jp flag
Problem sorted, another step into the deep unknown :) . Thank you very much.
MikroPower avatar
ro flag
Does it work? Or do you have installed Windows again? I wrote 4 little scripts, which I can activate with keyboard-shortcuts (brightness-plus, brightness-minus, brightness-zero, brightness-standard), so that I can change it over the keyboard easily.
anzacpi avatar
jp flag
It works really well... I will never go back to Windows... I am running Ubuntu 20.4 on a 2016 iMac. I have been unable to remove the iMac start files on one of the partitions and it slows the start procedure. I dont want to format the partition in case it holds the drivers for my iMac. As I said... Its a whole new ball game for me..
MikroPower avatar
ro flag
If this method works, show it to other people with a checkmark or upvote. So you can help other people with the same problem to find the right answer.
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