Score:0

Unable to reduce screen brightness using Fn key in 20.04

tc flag

I have a

  • Lenovo P51 laptop
  • Ubuntu 20.04
  • Fn+F5 and Fn+F6 are the brightness up/down keys

Current behaviour:

  • Pressing Fn+F6 increases the brightness and shows the brightness meter OSD
  • But pressing Fn+F5 just shows a circle with a line through it(⊘) on the OSD
  • I can increase and decrease brightness using the slider in Power settings

Expected behaviour:

  • Pressing Fn+F5 should display the brightness OSD while reducing the brightness one step

Findings:

  • xdotool key XF86MonBrightnessDown does the same as Fn+F5
  • xdotool key XF86MonBrightnessUp does the same as Fn+F6
  • XF86MonBrightnessDown is bound to /org/gnome/settings-daemon/plugins/media-keys/screen-brightness-down-static in Dconf.

Question:
What function is Fn+F5 calling?
If it is calling the reduced brightness function, why does it show the "⊘" symbol?

Update:
It is now working after a month and some Ubuntu updates.

mangohost

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