Arch Linux

prolific

Member

Registered: 2020-11-12

Posts: 4

Brightness not changing - Lenovo Legion 5Pi (15IMH05H)

I recently bought a new Legion 5Pi with CPU - Intel i7 10750H & GPU- Nvidia RTX 2060
The system is running both Windows 10 and Arch Linux (5.9.10-arch1-1) with Gnome (3.38.2)
Nvidia Driver Version: 455.45.01

Everything else seems to be working fine but I am unable to change the brightness of the display.

ls /sys/class/backlight
intel_backlight

cat /sys/class/backlight/intel_backlight/max_brightness 
26666

cat /sys/class/backlight/intel_backlight/brightness
18746

Physical Brightness keys seems to be changing the brightness values but it is not having any affect on the display.
Weirdly the max brightness value present in the above file is 26666 while I read somewhere that it should be around 300 or something (Not sure if this is an issue)

Tried everything under heading ACPI at https://wiki.archlinux.org/index.php/backlight
As brightness values in the above file in correctly changing so not sure if any other utility mentioned on the page would provide any additional help.

xbacklight -set 50

is not doing anything. Not even changing the values in the above file.

What's working:
I can boot into windows and change the brightness without any issue. The brightness set in windows stays so I can just reboot into arch afterwards.
This is just a temporary hack as I cannot switch OS every time I have to change the brightness

Additional Info - Shouldn't have any affect since the brightness was not working even before setting these up
Using tlp, optimus manager with PCI-Express Runtime D3 (RTD3) Power Management, xorg server

Please let me know if I can share any further details to help resolve this issue.

Mcmirande

Member

Registered: 2020-11-09

Posts: 4

Re: Brightness not changing - Lenovo Legion 5Pi (15IMH05H)

Hi, I've the same problem with the same computer and hoping for a solution.

I overcame it temporarily with  brightness-controller-git  which allows to change the brightness once started the computer, but still not with the native buttons of the keyboard.

OFF TOPIC: Also, if you have problems with the touchpad right button, I incidentally discovered that executing 

 sudo udevadm trigger 

in the terminal each time you start the computer, it works

Cheers, Marcos.

prolific

Member

Registered: 2020-11-12

Posts: 4

Re: Brightness not changing - Lenovo Legion 5Pi (15IMH05H)

I overcame it temporarily with  brightness-controller-git  which allows to change the brightness once started the computer, but still not with the native buttons of the keyboard.

Quick look at the source code and dependencies indicates that brightness-controller-git is using xrandr under the hood which If I am not wrong only changes the color of the display which then creates an illusion of change in brightness. I don't think this would improve battery life in anyway since the change is only due to software level manipulation. I would prefer switching to windows for changing the brightness and then reboot over xrandr.

Also you don't need a separate utility for that. You can try: https://wiki.archlinux.org/index.php/ba … ith_xrandr

OFF TOPIC: Also, if you have problems with the touchpad right button, I incidentally discovered that executing

sudo udevadm trigger 

in the terminal each time you start the computer, it works

wow...I didn't really notice that the right button click was not working. I was just using two finger tap for right click which always works. Now that you have pointed it out, it bugs me
Your solution for right click seems to be working but for some reason it then disables the tap to click (both left and right clicks). Anyways, this is not a big deal for me. My primary concern at the moment is only brightness.

Thanks for your inputs
Do let me know if you faced any other issue or tried anything else that worked.

Mcmirande

Member

Registered: 2020-11-09

Posts: 4

Re: Brightness not changing - Lenovo Legion 5Pi (15IMH05H)

Ahh, I never used the two finger tap. Maybe it's faster or easier once you're accustomed to use it.

And concerning the brightness almost surely you're right.  I didn't thought in improving battery life, actually.

Thanks, Marcos.

EDIT: I just tested directly with

xrandr

and corroborated what you said.  So... I'm also looking for a solution on Lenovo Legion brightness

Last edited by Mcmirande (2020-11-30 23:59:51)

prolific

Member

Registered: 2020-11-12

Posts: 4

Re: Brightness not changing - Lenovo Legion 5Pi (15IMH05H)

Update: Issue still not resolved.
Linux: 5.11.4-arch1-1

Opened an issue for this at drm/intel: https://gitlab.freedesktop.org/drm/intel/-/issues/3139

If anyone else is having the same device and also has further information to add then please feel free to jump in and add comments at the above link to help speed up the process of fixing.

gavsiu

Member

Registered: 2016-04-08

Posts: 29

Re: Brightness not changing - Lenovo Legion 5Pi (15IMH05H)

I subscribed hoping you guys could find a solution to the backlight issue. Just adding that I have a different laptop with similar specs.

Lenovo Legion 7i
Host: 81YT Lenovo Legion 7 15IMH05
Kernel: 5.11.4-arch1-1
CPU: Intel i7-10750H (12) @ 5.000GHz
GPU: NVIDIA GeForce RTX 2060 Mobile
GPU: Intel UHD Graphics

Off topic, but do you guys have working internal speakers? Mine doesn't work. I only get sound with external speakers or bluetooth.

prolific

Member

Registered: 2020-11-12

Posts: 4

Re: Brightness not changing - Lenovo Legion 5Pi (15IMH05H)

I subscribed hoping you guys could find a solution to the backlight issue. Just adding that I have a different laptop with similar specs.

Lenovo Legion 7i
Host: 81YT Lenovo Legion 7 15IMH05
Kernel: 5.11.4-arch1-1
CPU: Intel i7-10750H (12) @ 5.000GHz
GPU: NVIDIA GeForce RTX 2060 Mobile
GPU: Intel UHD Graphics

Off topic, but do you guys have working internal speakers? Mine doesn't work. I only get sound with external speakers or bluetooth.

Legion 7i backlight issue is already resolved: https://gitlab.freedesktop.org/drm/intel/-/issues/2561
A friend of mine has this laptop so I have already confirmed this with him and it is working. You only need to add `i915.enable_dpcd_backlight=1` as kernel parameter and your backlight issue will be resolved. After some time you will also get updated drivers from upstream and then you will also not be required to add this kernel parameter.
Regarding sound: https://bugzilla.kernel.org/show_bug.cgi?id=208555 [Pending]

Like you mentioned Legion 5Pi is a different device and the brightness issue is still present:
https://gitlab.freedesktop.org/drm/intel/-/issues/3139

Sound on Legion 5pi works just fine.

gavsiu

Member

Registered: 2016-04-08

Posts: 29

Re: Brightness not changing - Lenovo Legion 5Pi (15IMH05H)

Legion 7i backlight issue is already resolved: https://gitlab.freedesktop.org/drm/intel/-/issues/2561
A friend of mine has this laptop so I have already confirmed this with him and it is working. You only need to add `i915.enable_dpcd_backlight=1` as kernel parameter and your backlight issue will be resolved. After some time you will also get updated drivers from upstream and then you will also not be required to add this kernel parameter.
Regarding sound: https://bugzilla.kernel.org/show_bug.cgi?id=208555 [Pending]

Like you mentioned Legion 5Pi is a different device and the brightness issue is still present:
https://gitlab.freedesktop.org/drm/intel/-/issues/3139

Sound on Legion 5pi works just fine.

Thanks for the info on the backlight. Just adding the kernel parameter didn't work. I probably have to patch the kernel, but I'm not too familiar with doing that. I might just wait.

I have seen the bug report regarding the sound before.

Thanks again.

strikingcheesecake

Member

From: South

Registered: 2021-03-13

Posts: 3

Re: Brightness not changing - Lenovo Legion 5Pi (15IMH05H)

Legion 7i backlight issue is already resolved: https://gitlab.freedesktop.org/drm/intel/-/issues/2561
A friend of mine has this laptop so I have already confirmed this with him and it is working. You only need to add `i915.enable_dpcd_backlight=1` as kernel parameter and your backlight issue will be resolved. After some time you will also get updated drivers from upstream and then you will also not be required to add this kernel parameter.
Regarding sound: https://bugzilla.kernel.org/show_bug.cgi?id=208555 [Pending]

Like you mentioned Legion 5Pi is a different device and the brightness issue is still present:
https://gitlab.freedesktop.org/drm/intel/-/issues/3139

Sound on Legion 5pi works just fine.

Thanks for the info on the backlight. Just adding the kernel parameter didn't work. I probably have to patch the kernel, but I'm not too familiar with doing that. I might just wait.

I have seen the bug report regarding the sound before.

Thanks again.

Maybe doesn't apply to your Legion unit, but have you tried removing these kernel parameters 'acpi_osi=linux, acpi_backlight=vendor' ? I added these on a test Thinkpad T14s (AMD) uni and the backlight stayed constant and couldn't be changed by the buttons FN+F5/F6 . Removing the lines and doing a cold reboot restored backlight function.

---

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I'm from the Sun OS era...:) |A mother | semi-geek
Currently re-learning Linux
__________________

gavsiu

Member

Registered: 2016-04-08

Posts: 29

Re: Brightness not changing - Lenovo Legion 5Pi (15IMH05H)

Legion 7i backlight issue is already resolved: https://gitlab.freedesktop.org/drm/intel/-/issues/2561
A friend of mine has this laptop so I have already confirmed this with him and it is working. You only need to add `i915.enable_dpcd_backlight=1` as kernel parameter and your backlight issue will be resolved. After some time you will also get updated drivers from upstream and then you will also not be required to add this kernel parameter.
Regarding sound: https://bugzilla.kernel.org/show_bug.cgi?id=208555 [Pending]

Like you mentioned Legion 5Pi is a different device and the brightness issue is still present:
https://gitlab.freedesktop.org/drm/intel/-/issues/3139

Sound on Legion 5pi works just fine.

Thanks for the info on the backlight. Just adding the kernel parameter didn't work. I probably have to patch the kernel, but I'm not too familiar with doing that. I might just wait.

I have seen the bug report regarding the sound before.

Thanks again.

Maybe doesn't apply to your Legion unit, but have you tried removing these kernel parameters 'acpi_osi=linux, acpi_backlight=vendor' ? I added these on a test Thinkpad T14s (AMD) uni and the backlight stayed constant and couldn't be changed by the buttons FN+F5/F6 . Removing the lines and doing a cold reboot restored backlight function.

My kernel parameters did not contain either 'acpi_osi=linux, acpi_backlight=vendor' when I added 'i915.enable_dpcd_backlight=1'. I have also tried those parameters before and they did nothing. Pretty sure I need to somehow patch the i915 driver. The gitlab link mentions the edid_quirk_list. I don't know where the actual i915 source is, but I'm guessing it's this? edid_quirk_list doesn't seem to mention Legion.

Also, what's the difference between i915 issues on gitlab.freedesktop.org and bugzilla.kernel.org?

Last edited by gavsiu (2021-03-22 17:18:00)