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lag-ubuntu
Paper Tape
Posts: 4
Registered: ‎08-19-2010
Location: GB
Views: 167
Message 1 of 7

X1 Extreme: Backlight brightness not working with Linux in Hybrid mode (Intel)

I'm trying to lower the brighness when 'Intel (power saving)' mode is enabled.

 

Not worried about key bindings for the moment - I'll cross that bridge when I come to it.

 

The biggest problem is that direct changes to the driver interface doens't seem to be having an effect:

 

  /sys/class/backlight/intel_backlight/brightness

 

I have tried variations of the following kernel command line parameters, to no avail:

 

  thinkpad-acpi.brightness_enable=1

  cpi_osi=linux

  acpi_brightness=vendor

 

If this situation is not resolved, I will have to return the laptop, which I'm at pains to do.

benoga
Fanfold Paper
Posts: 1
Registered: ‎11-04-2019
Location: CH
Views: 155
Message 2 of 7

Re: X1 Extreme: Backlight brightness not working with Linux in Hybrid mode (Intel)

Same Problem here. Not Brightness on Linux Hybrid Driver.

Lenovo Employee DaveOber
Lenovo Employee
Posts: 75
Registered: ‎12-17-2018
Location: US
Views: 126
Message 3 of 7

Re: X1 Extreme: Backlight brightness not working with Linux in Hybrid mode (Intel)

Do you have an OLED on non-OLED panel also what is you BIOS level this informwation would assist in solving your issue.

lag-ubuntu
Paper Tape
Posts: 4
Registered: ‎08-19-2010
Location: GB
Views: 124
Message 4 of 7

Re: X1 Extreme: Backlight brightness not working with Linux in Hybrid mode (Intel)

I used the firmware updater tool to upgrade to the latest BIOS.

 

The screen is 15.6" UHD LED Backlight, OLED. 

Lenovo Employee DaveOber
Lenovo Employee
Posts: 75
Registered: ‎12-17-2018
Location: US
Views: 119
Message 5 of 7

Re: X1 Extreme: Backlight brightness not working with Linux in Hybrid mode (Intel)

The update for OLED brightness controls from Intel went into the 5.3 kernel, I know that Fedora 31 and Debian 10 testing stream are already using this kernel or higher other Distros may not have moved that far and you would need to manually update the kernel to get it properly working on those 

lag-ubuntu
Paper Tape
Posts: 4
Registered: ‎08-19-2010
Location: GB
Views: 116
Message 6 of 7

Re: X1 Extreme: Backlight brightness not working with Linux in Hybrid mode (Intel)

I'm on 5.3.0-19.

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Lenovo Employee DaveOber
Lenovo Employee
Posts: 75
Registered: ‎12-17-2018
Location: US
Views: 113
Message 7 of 7

Re: X1 Extreme: Backlight brightness not working with Linux in Hybrid mode (Intel)

I rechecked my notes and it is not the 5.3 but it was put in in 5.4 rc4  here is the patch  

https://patchwork.freedesktop.org/patch/334989/?series=67595&rev=2 

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