As the title suggests, I upgraded my Dell XPS 15 laptop to 14.10 and now the brightness is stuck at the lowest level. The fn+F4/F5 displays the brightness notifications but the brightness level of the screen does not change.
Things I have tried that did not help:
Switching from Nvidia drivers to Nouveau did not help.
xrandr does increase the gamma a tiny bit:
xrandr --output "LVDS1" --brightness "1"
Many questions suggest either adding or subtracting acpi_backlight to your /etc/default/grub file, which did not help either:
GRUB_CMDLINE_LINUX_DEFAULT="quiet acpi_backlight=vendor splash"
I also tried writing directly to the brightness file:
echo 4000 | sudo tee /sys/class/backlight/intel_backlight/brightness
There seem to be many questions of this type:
Which package should I be looking at to file a bug? What information would help?
Does anyone have a solution I should try that is not listed above?
Update: Booting from a live USB (I think it was 13.04) reset the brightness to the maximum. Booting back the 14.10 the screen stayed bright, but the brightness controls still don't do anything. Feels like progress. :)