Tthere are 8 acpi_video directories in /sys/class/backlight/ , but none of them can adjust the brightness. >From my point of view, the brightness is only controlled by an AV board, so we can't adjust the brightness through ACPI or WMI.
BTW, it doesn't use any dell_wmi driver, and I can't insert dell_wmi nor dell_wmi_aio driver, the WMI GUID it has is not listed in the driver, that means it has a non standard WMI GUID. So, I think we can do nothing for this machine. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1203982 Title: [Dell Inspiron One 2020] Unable to adjust screen brightness Status in “linux” package in Ubuntu: Confirmed Bug description: CID: 201301-12632 Dell Inspiron One 2020 On this all-in-one desktop, I was unable to adjust screen brightness in System Settings/Brightness and Lock The slidebar of brightness level could be freely adjusted , but nothing happens. The OSD works fine on this system, screen brightness could be adjusted through it But the change is not reflected in "Brightness and Lock" ProblemType: Bug DistroRelease: Ubuntu 12.04 Package: linux-image-3.5.0-23-generic 3.5.0-23.35~precise1 ProcVersionSignature: Ubuntu 3.5.0-23.35~precise1-generic 188.8.131.52 Uname: Linux 3.5.0-23-generic x86_64 AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.25. AplayDevices: **** List of PLAYBACK Hardware Devices **** card 0: PCH [HDA Intel PCH], device 0: ALC662 rev3 Analog [ALC662 rev3 Analog] Subdevices: 1/1 Subdevice #0: subdevice #0 ApportVersion: 2.0.1-0ubuntu17.1 Architecture: amd64 ArecordDevices: **** List of CAPTURE Hardware Devices **** card 0: PCH [HDA Intel PCH], device 0: ALC662 rev3 Analog [ALC662 rev3 Analog] Subdevices: 1/1 Subdevice #0: subdevice #0 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: ubuntu 1575 F.... pulseaudio Card0.Amixer.info: Card hw:0 'PCH'/'HDA Intel PCH at 0xf7d00000 irq 42' Mixer name : 'Realtek ALC662 rev3' Components : 'HDA:10ec0662,10280579,00100300' Controls : 17 Simple ctrls : 8 Date: Tue Jul 23 02:47:00 2013 HibernationDevice: RESUME=UUID=0c9d79aa-e95b-4c59-b8e4-c51b862b1982 InstallationMedia: Ubuntu 12.04.2 LTS "Precise Pangolin" - Release amd64 (20130213) MachineType: Dell Inc. Inspiron One 2020 MarkForUpload: True ProcEnviron: TERM=xterm PATH=(custom, no user) LANG=en_US.UTF-8 SHELL=/bin/bash ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.5.0-23-generic root=UUID=36293b43-a3d7-4ff2-a6f7-608f8002990b ro quiet splash initcall_debug vt.handoff=7 RelatedPackageVersions: linux-restricted-modules-3.5.0-23-generic N/A linux-backports-modules-3.5.0-23-generic N/A linux-firmware 1.79.1 SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 01/30/2013 dmi.bios.vendor: Dell Inc. dmi.bios.version: A05 dmi.board.name: 03KE02 dmi.board.vendor: Dell Inc. dmi.board.version: X02 dmi.chassis.type: 3 dmi.chassis.vendor: Dell Inc. dmi.modalias: dmi:bvnDellInc.:bvrA05:bd01/30/2013:svnDellInc.:pnInspironOne2020:pvr:rvnDellInc.:rn03KE02:rvrX02:cvnDellInc.:ct3:cvr: dmi.product.name: Inspiron One 2020 dmi.sys.vendor: Dell Inc. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1203982/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : email@example.com Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp