[solved] Enable screen brightness control on Lenovo B570

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[solved] Enable screen brightness control on Lenovo B570

Postby Onsemeliot » 2020-05-05 11:15

A friend was running Lubuntu 18.04 on a Lenovo B570 laptop. It basically did work there in dual boot with Windows but it developed more and more issues. Most notably in the end the system just went dead each time it went to sleep. And on the next boot afterwards it was always necessary to run fsck in order to be able to boot the OS again. Originally I thought this might be due to broken sectors on the hard disk.

Nevertheless, I decided to try a clean install with Debian Buster LXDE. Since Debian doesn't actually share the same issue I guess it was just something related to some mess in the old installation and not a hardware problem.

I installed the Xfce engery management tools and could adjust the power saving options with that. Now the system doesn't vanish after going to sleep mode any more. Debian Buster LXDE behaves rather nicely in general.

But unfortunately, I am so far unable to get all 2nd function key controls working. I can change the audio volume but most importantly I can't adapt the screen brightness. Since the battery isn't so great any more it is relevant if the screen runs with full brightness all the time. I have searched for anything related to it but didn't find any mentioning of this issue for GNU/Linux systems. Maybe nobody tried to run Debian/LXDE on the Lenovo B570 so far.

But the problem seems to sit deeper because the GUI slider doesn't do anything either. I found out that there is at least one last bios update 44CN43WW.exe (current bios version on the device: 44CN42WW) available but it is only provided as Windows executable and I don't know how I would be able to use it for updating when not running Windows. Besides, the release notes don't mention any fix for something like my issue. But that doesn't probably mean much since Lenovo obviously wasn't planing to consider GNU/Linux for this device anyway.

Please tell me if anyone reading this can provide a hint for how to enable screen brightness control on this device!
Last edited by Onsemeliot on 2020-05-05 13:24, edited 1 time in total.
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Re: Howto enable screen brightness control on Lenovo B570

Postby Head_on_a_Stick » 2020-05-05 11:56

Have you tried the kernel parameters listed here?

How about the xbacklight utility? That doesn't work with the default modesetting DDX driver but you could try it with xserver-xorg-video-intel and if that works then bind the keys to the command.

As a last resort use a script or function to write a value directly to sysfs, here's one I use:
Code: Select all
empty@E485 ~ % cat /usr/local/bin/lt
sudo tee /sys/class/backlight/amdgpu_bl0/brightness <<<"$1"
empty@E485 ~ %

^ That's for an AMD card (obviously) — I call it with the desired backlight setting appended, for example:
Code: Select all
lt 100

The max_brightness file shows the available numerical range.

EDIT: perhaps try FreeDOS to run the firmware update .exe file supplied by Lenovo.
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Re: Howto enable screen brightness control on Lenovo B570

Postby trinidad » 2020-05-05 12:13

Eventually Linux support for Lenovo is going to get better given Fedoras new involvement with them. You might want to check if they have solutions for your hardware.

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Re: Howto enable screen brightness control on Lenovo B570

Postby Onsemeliot » 2020-05-05 13:10

arochester wrote:https://askubuntu.com/questions/57236/unable-to-change-brightness-in-a-lenovo-laptop ?

Thank you all for your incredibly quick answers. I followed the quoted solution since it seemed the easiest to try out and it did the trick for at least enabling the GUI control. The key binding was an independent issue. But after activating the option that the Xfce power manager should administrate the screen brightness buttons even the key binding works. :D
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