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.
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https://bugs.launchpad.net/bugs/1782177
Title:
Screen sometimes jumps to full brightness on resume from suspend
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