Acer Aspire 5742Z No Screen Brightness Control
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
linux (Ubuntu) |
Expired
|
Undecided
|
Unassigned |
Bug Description
The screen brightness controls on this laptop do not work in Ubuntu 10.10 with all updates installed to-date.
Pressing the Fn+arrow keys will bring up the brightness notification and indicate a change, but nothing happens. The power control is unable to dim the screen when switching to battery power or when idle.
There are many other bugs in Launchpad for brightness problems with laptops, but none specifically for the Acer Aspire 5742Z. The similar laptops appear to have other problems I don't have, and fixes suggested in those bugs (nomodeset, acpi_backlight=
Log files attached of various systems:
cat /proc/version_
dmesg > dmesg.log
sudo lspci -vnvn > lspci-vnvn.log
sudo acpidump -o acpidump.txt
sudo acpidump -o acpidump.txt
grep -r . /proc/acpi/video >grep-video.txt
tags: | added: kj-triage |
Changed in linux (Ubuntu): | |
status: | New → Confirmed |
description: | updated |
Additional testing: Adding "acpi_osi=" (without quotes) with nothing after the equal sign to the GRUB_CMDLINE_ LINUX_DEFAULT line in /etc/default/grub makes the brightness keys work complete with 10 levels of brightness. However, the notification no longer works.
Also, connecting and removing the AC adapter does not change the brightness, even though power management is set to do so. Curiously, hitting brightness up key after unplugging the AC adapter drops the brightness to 20%, suggesting the power management tried to set the brightness value, but it didn't actually change the value. The opposite happens when plugging back into AC.