Public bug reported: At night, I usually turn my brightness down as far as it will go using the brightness keys. This makes it dim, but visible and not off. When I walk away for a while, the screen goes to sleep, and when I come back and move the mouse, the screen jumps to full brightness, which is very unpleasant at night. Investigating, it seems that the brightness in intel_backlight is getting reset to 4437, but the one in acpi_video0 reads 0.
$ for file in brightness max_brightness actual_brightness; > do > for directory in /sys/class/backlight/intel_backlight/ /sys/class/backlight/acpi_video0/ > do > echo $directory$file : $(cat $directory$file) > done > done /sys/class/backlight/intel_backlight/brightness : 4437 /sys/class/backlight/acpi_video0/brightness : 0 /sys/class/backlight/intel_backlight/max_brightness : 4437 /sys/class/backlight/acpi_video0/max_brightness : 15 /sys/class/backlight/intel_backlight/actual_brightness : 4437 /sys/class/backlight/acpi_video0/actual_brightness : 0 After I press the button to increase the brightness one notch, they are back in sync, and then I can turn it back down as well. $ for file in brightness max_brightness actual_brightness; > do > for directory in /sys/class/backlight/intel_backlight/ /sys/class/backlight/acpi_video0/ > do > echo $directory$file : $(cat $directory$file) > done > done /sys/class/backlight/intel_backlight/brightness : 53 /sys/class/backlight/acpi_video0/brightness : 1 /sys/class/backlight/intel_backlight/max_brightness : 4437 /sys/class/backlight/acpi_video0/max_brightness : 15 /sys/class/backlight/intel_backlight/actual_brightness : 53 /sys/class/backlight/acpi_video0/actual_brightness : 1 This is on a fresh install of xubuntu 18.04. Seems like a regression from 16.04, which I ran on the same laptop without this issue. ** Affects: xfce4-power-manager (Ubuntu) Importance: Undecided Status: New ** Description changed: At night, I usually turn my brightness down as far as it will go using the brightness keys. This makes it dim, but visible and not off. When I walk away for a while, the screen goes to sleep, and when I come back and move the mouse, the screen jumps to full brightness, which is very unpleasant at night. Investigating, it seems that the brightness in intel_backlight is getting reset to 4437, but the one in acpi_video0 reads 0. - $ for file in brightness max_brightness actual_brightness; - > do - > for directory in /sys/class/backlight/intel_backlight/ /sys/class/backlight/acpi_video0/ - > do - > echo $directory$file : $(cat $directory$file) - > done - > done - /sys/class/backlight/intel_backlight/brightness : 4437 - /sys/class/backlight/acpi_video0/brightness : 0 - /sys/class/backlight/intel_backlight/max_brightness : 4437 - /sys/class/backlight/acpi_video0/max_brightness : 15 - /sys/class/backlight/intel_backlight/actual_brightness : 4437 - /sys/class/backlight/acpi_video0/actual_brightness : 0 + $ for file in brightness max_brightness actual_brightness; + > do + > for directory in /sys/class/backlight/intel_backlight/ /sys/class/backlight/acpi_video0/ + > do + > echo $directory$file : $(cat $directory$file) + > done + > done + /sys/class/backlight/intel_backlight/brightness : 4437 + /sys/class/backlight/acpi_video0/brightness : 0 + /sys/class/backlight/intel_backlight/max_brightness : 4437 + /sys/class/backlight/acpi_video0/max_brightness : 15 + /sys/class/backlight/intel_backlight/actual_brightness : 4437 + /sys/class/backlight/acpi_video0/actual_brightness : 0 After I press the button to increase the brightness one notch, they are back in sync, and then I can turn it back down as well. - $ for file in brightness max_brightness actual_brightness; - > do - > for directory in /sys/class/backlight/intel_backlight/ /sys/class/backlight/acpi_video0/ - > do - > echo $directory$file : $(cat $directory$file) - > done - > done - /sys/class/backlight/intel_backlight/brightness : 53 - /sys/class/backlight/acpi_video0/brightness : 1 - /sys/class/backlight/intel_backlight/max_brightness : 4437 - /sys/class/backlight/acpi_video0/max_brightness : 15 - /sys/class/backlight/intel_backlight/actual_brightness : 53 - /sys/class/backlight/acpi_video0/actual_brightness : 1 + $ for file in brightness max_brightness actual_brightness; + > do + > for directory in /sys/class/backlight/intel_backlight/ /sys/class/backlight/acpi_video0/ + > do + > echo $directory$file : $(cat $directory$file) + > done + > done + /sys/class/backlight/intel_backlight/brightness : 53 + /sys/class/backlight/acpi_video0/brightness : 1 + /sys/class/backlight/intel_backlight/max_brightness : 4437 + /sys/class/backlight/acpi_video0/max_brightness : 15 + /sys/class/backlight/intel_backlight/actual_brightness : 53 + /sys/class/backlight/acpi_video0/actual_brightness : 1 + + This is on a fresh install of xubuntu 18.04. Seems like a regression + from 16.04, which I ran on the same laptop without this issue. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1782177 Title: Screen sometimes jumps to full brightness on resume from suspend To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xfce4-power-manager/+bug/1782177/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs