I just found a very promising workaround here: http://www.uluga.ubuntuforums.org/showthread.php?t=1446943
I have not yet fully tried it, but I have verified that the two core ideas also work for me: a) When I press the brightness buttons the value in /sys/class/backlight/acpi_video0/brightness changes. b) When I do: "sudo setpci -s 00:02.0 F4.B=a1" the brightness indeed changes Before you try anything best read the thread yourself. Especially check with lspci |grep VGA whether 00:02.0 is the right address for your system. And be prepared for the fact that "sudo setpci -s 00:02.0 F4.B=0" gives you a pitch black screen :-) . Thanks to FunkyRider and Skildron ** Description changed: - [Workaround] + [Workaround 1] For Acer Extensa 5635Z with bios version V0.3219 or newer adding acpi_osi=Linux acpi_backlight=legacy as boot parameter resolves the issue. + + [Workaround 2] + See comment #28. [Report] ubuntu lucid-desktop-amd64 20100206 (booting the iso from hd via grub2 loopback) on acer extensa 5635z: the backlight settings are simply ignored. the keys work, the notification works (changing according to the key presses), but the display always stays at the same full brightness. boot with acpi=off: backlight dimming works. 10 levels are available. surprisingly there is no notification. (notification for sound is there) warning: a short press of the power button kills the power immediately! ProblemType: Bug AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.21. Architecture: amd64 ArecordDevices: **** List of CAPTURE Hardware Devices **** card 0: Intel [HDA Intel], device 0: CONEXANT Analog [CONEXANT Analog] Subdevices: 1/1 Subdevice #0: subdevice #0 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: ubuntu 2832 F.... pulseaudio CRDA: Error: [Errno 2] No such file or directory Card0.Amixer.info: Card hw:0 'Intel'/'HDA Intel at 0xf0700000 irq 22' Mixer name : 'Conexant CX20561 (Hermosa)' Components : 'HDA:14f15051,10250253,00100000' Controls : 14 Simple ctrls : 7 Date: Sat Feb 6 11:04:34 2010 DistroRelease: Ubuntu 10.04 LiveMediaBuild: Ubuntu 10.04 "Lucid Lynx" - Alpha amd64 (20100206) MachineType: Acer Extensa 5635Z Package: linux-image-2.6.32-12-generic 2.6.32-12.17 ProcCmdLine: BOOT_IMAGE=(loop)/casper/vmlinuz boot=casper iso-scan/filename=/boot/iso/hostname/lucid-desktop-amd64.iso noprompt -- ProcEnviron: LANG=en_US.UTF-8 SHELL=/bin/bash ProcVersionSignature: Ubuntu 2.6.32-12.17-generic Regression: No RelatedPackageVersions: linux-firmware 1.29 Reproducible: Yes SourcePackage: linux TestedUpstream: No Uname: Linux 2.6.32-12-generic x86_64 dmi.bios.date: 05/07/2009 dmi.bios.vendor: Phoenix dmi.bios.version: V0.3213 dmi.board.name: BA50-MV dmi.board.vendor: Acer dmi.board.version: Not Applicable dmi.chassis.type: 10 dmi.chassis.vendor: Acer dmi.chassis.version: N/A dmi.modalias: dmi:bvnPhoenix:bvrV0.3213:bd05/07/2009:svnAcer:pnExtensa5635Z:pvrNotApplicable:rvnAcer:rnBA50-MV:rvrNotApplicable:cvnAcer:ct10:cvrN/A: dmi.product.name: Extensa 5635Z dmi.product.version: Not Applicable dmi.sys.vendor: Acer -- lucid extensa 5635z backlight dimming not working at all https://bugs.launchpad.net/bugs/518002 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
