I can confirm this bug is still present in 11.04 with a fully up-to-date system, kernel Ubuntu SMP Mon Apr 11 03:31:24 UTC 2011 (Ubuntu 2.6.38-8.42-generic 2.6.38.2).
I have an ASUS U81A laptop and backlight brightness was not adjustable with stock settings (it DID worked in Ubuntu 10.04). dmesg shows: [ 1590.777213] ACPI Exception: AE_AML_BUFFER_LIMIT, Index (0x000000000000001B) is beyond end of object (20110112/exoparg2-418) [ 1590.777228] ACPI Error: Method parse/execution failed [\_SB_.PCI0.SBRG.EC0_.STBR] (Node ffff88013763f2d0), AE_AML_BUFFER_LIMIT (20110112/psparse-536) [ 1590.777243] ACPI Error: Method parse/execution failed [\_SB_.PCI0.VGA_.LCDD._BCM] (Node ffff880137638578), AE_AML_BUFFER_LIMIT (20110112/psparse-536) [ 1590.777259] ACPI Error: Evaluating _BCM failed (20110112/video-365) [ 1590.777266] ACPI: Failed to switch the brightness [ 1590.780977] ACPI Exception: AE_AML_BUFFER_LIMIT, Index (0x000000000000001B) is beyond end of object (20110112/exoparg2-418) [ 1590.780992] ACPI Error: Method parse/execution failed [\_SB_.PCI0.SBRG.EC0_.STBR] (Node ffff88013763f2d0), AE_AML_BUFFER_LIMIT (20110112/psparse-536) [ 1590.781008] ACPI Error: Method parse/execution failed [\_SB_.PCI0.VGA_.LCDD._BCM] (Node ffff880137638578), AE_AML_BUFFER_LIMIT (20110112/psparse-536) [ 1590.781024] ACPI Error: Evaluating _BCM failed (20110112/video-365) [ 1590.782442] ACPI Exception: AE_AML_BUFFER_LIMIT, Index (0x0000000000000021) is beyond end of object (20110112/exoparg2-418) [ 1590.782458] ACPI Error: Method parse/execution failed [\_SB_.PCI0.SBRG.EC0_.STBR] (Node ffff88013763f2d0), AE_AML_BUFFER_LIMIT (20110112/psparse-536) [ 1590.782473] ACPI Error: Method parse/execution failed [\_SB_.PCI0.VGA_.LCDD._BCM] (Node ffff880137638578), AE_AML_BUFFER_LIMIT (20110112/psparse-536) [ 1590.782489] ACPI Error: Evaluating _BCM failed (20110112/video-365) [ 1590.786929] ACPI Exception: AE_AML_BUFFER_LIMIT, Index (0x0000000000000021) is beyond end of object (20110112/exoparg2-418) [ 1590.786943] ACPI Error: Method parse/execution failed [\_SB_.PCI0.SBRG.EC0_.STBR] (Node ffff88013763f2d0), AE_AML_BUFFER_LIMIT (20110112/psparse-536) [ 1590.786958] ACPI Error: Method parse/execution failed [\_SB_.PCI0.VGA_.LCDD._BCM] (Node ffff880137638578), AE_AML_BUFFER_LIMIT (20110112/psparse-536) [ 1590.786973] ACPI Error: Evaluating _BCM failed (20110112/video-365) I did the GRUB_CMDLINE_LINUX="acpi_backlight=vendor" workaround (no change in ACPI!) and now backlight works. dmesg now shows other errors: [ 1532.974709] ACPI Error: Result stack is empty! State=ffff88011421b800 (20110112/dswstate-98) [ 1532.974722] ACPI Exception: AE_AML_NO_RETURN_VALUE, Missing or null operand (20110112/dsutils-646) [ 1532.974730] ACPI Exception: AE_AML_NO_RETURN_VALUE, While creating Arg 1 (20110112/dsutils-763) [ 1532.974739] ACPI Error: Method parse/execution failed [\_SB_.PCI0.VGA_.DWBL] (Node ffff8801376387f8), AE_AML_NO_RETURN_VALUE (20110112/psparse-536) [ 1532.974754] ACPI Error: Method parse/execution failed [\_SB_.PCI0.SBRG.EC0_._Q0E] (Node ffff88013763feb0), AE_AML_NO_RETURN_VALUE (20110112/psparse-536) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/566193 Title: luminosity screen on a laptop cannot be set -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
