This is a new problem I'm facing in 13.04, and is not related to what worked for 12.10 or earlier.
In 12.10, I had the
acpi_backlight=vendor in my grub in order to make the brightness setting work. However, this does not work on 13.04. I don't even see a brightness bar.
To change that, I tried
acpi_osi= and the brightness bar appeared in the system settings. Moving it doesn't change the brightness, but using my hotkeys does.
Since Ubuntu doesn't remember the brightness settings between boots, I had a script that would adjust it during startup. Now, even that doesn't seem to work. Only my hotkeys work at the moment.
- Model: Acer Aspire E1-571
- Processor: Intel® Core™ i3-3110M CPU @ 2.40GHz × 4
- Graphics: Intel® Ivybridge Mobile
- OS type: 64bits
Things I've tried
acpi_osi=using this makes my hotkeys work, but the brightness slider doesn't work
acpi_osi='!Windows 2012' acpi_backlight=vendor